Apply modernize-use-override (2nd iteration)

Summary:
Use C++11’s override and remove virtual where applicable.
Change are automatically generated.

Reviewed By: Orvid

Differential Revision: D14090024

fbshipit-source-id: 1e9432e87d2657e1ff0028e15370a85d1739ba2a

cache/cache_test.cc

@@ -73,8 +73,7 @@ class CacheTest : public testing::TestWithParam<std::string> {
     current_ = this;
   }
 
-  ~CacheTest() {
+  ~CacheTest() override {}
-  }
 
   std::shared_ptr<Cache> NewCache(size_t capacity) {
     auto type = GetParam();

cache/clock_cache.cc

@@ -240,32 +240,29 @@ class ClockCacheShard : public CacheShard {
   typedef tbb::concurrent_hash_map<CacheKey, CacheHandle*, CacheKey> HashTable;
 
   ClockCacheShard();
-  ~ClockCacheShard();
+  ~ClockCacheShard() override;
 
   // Interfaces
-  virtual void SetCapacity(size_t capacity) override;
+  void SetCapacity(size_t capacity) override;
-  virtual void SetStrictCapacityLimit(bool strict_capacity_limit) override;
+  void SetStrictCapacityLimit(bool strict_capacity_limit) override;
-  virtual Status Insert(const Slice& key, uint32_t hash, void* value,
+  Status Insert(const Slice& key, uint32_t hash, void* value, size_t charge,
-                        size_t charge,
+                void (*deleter)(const Slice& key, void* value),
-                        void (*deleter)(const Slice& key, void* value),
+                Cache::Handle** handle, Cache::Priority priority) override;
-                        Cache::Handle** handle,
+  Cache::Handle* Lookup(const Slice& key, uint32_t hash) override;
-                        Cache::Priority priority) override;
-  virtual Cache::Handle* Lookup(const Slice& key, uint32_t hash) override;
   // If the entry in in cache, increase reference count and return true.
   // Return false otherwise.
   //
   // Not necessary to hold mutex_ before being called.
-  virtual bool Ref(Cache::Handle* handle) override;
+  bool Ref(Cache::Handle* handle) override;
-  virtual bool Release(Cache::Handle* handle,
+  bool Release(Cache::Handle* handle, bool force_erase = false) override;
-                       bool force_erase = false) override;
+  void Erase(const Slice& key, uint32_t hash) override;
-  virtual void Erase(const Slice& key, uint32_t hash) override;
   bool EraseAndConfirm(const Slice& key, uint32_t hash,
                        CleanupContext* context);
-  virtual size_t GetUsage() const override;
+  size_t GetUsage() const override;
-  virtual size_t GetPinnedUsage() const override;
+  size_t GetPinnedUsage() const override;
-  virtual void EraseUnRefEntries() override;
+  void EraseUnRefEntries() override;
-  virtual void ApplyToAllCacheEntries(void (*callback)(void*, size_t),
+  void ApplyToAllCacheEntries(void (*callback)(void*, size_t),
-                                      bool thread_safe) override;
+                              bool thread_safe) override;
 
  private:
   static const uint32_t kInCacheBit = 1;
@@ -685,31 +682,31 @@ class ClockCache : public ShardedCache {
     SetStrictCapacityLimit(strict_capacity_limit);
   }
 
-  virtual ~ClockCache() { delete[] shards_; }
+  ~ClockCache() override { delete[] shards_; }
 
-  virtual const char* Name() const override { return "ClockCache"; }
+  const char* Name() const override { return "ClockCache"; }
 
-  virtual CacheShard* GetShard(int shard) override {
+  CacheShard* GetShard(int shard) override {
     return reinterpret_cast<CacheShard*>(&shards_[shard]);
   }
 
-  virtual const CacheShard* GetShard(int shard) const override {
+  const CacheShard* GetShard(int shard) const override {
     return reinterpret_cast<CacheShard*>(&shards_[shard]);
   }
 
-  virtual void* Value(Handle* handle) override {
+  void* Value(Handle* handle) override {
     return reinterpret_cast<const CacheHandle*>(handle)->value;
   }
 
-  virtual size_t GetCharge(Handle* handle) const override {
+  size_t GetCharge(Handle* handle) const override {
     return reinterpret_cast<const CacheHandle*>(handle)->charge;
   }
 
-  virtual uint32_t GetHash(Handle* handle) const override {
+  uint32_t GetHash(Handle* handle) const override {
     return reinterpret_cast<const CacheHandle*>(handle)->hash;
   }
 
-  virtual void DisownData() override { shards_ = nullptr; }
+  void DisownData() override { shards_ = nullptr; }
 
  private:
   ClockCacheShard* shards_;

cache/lru_cache_test.cc

@@ -15,7 +15,7 @@ namespace rocksdb {
 class LRUCacheTest : public testing::Test {
  public:
   LRUCacheTest() {}
-  ~LRUCacheTest() { DeleteCache(); }
+  ~LRUCacheTest() override { DeleteCache(); }
 
   void DeleteCache() {
     if (cache_ != nullptr) {

db/c.cc

@@ -208,13 +208,10 @@ struct rocksdb_compactionfilter_t : public CompactionFilter {
   const char* (*name_)(void*);
   unsigned char ignore_snapshots_;
 
-  virtual ~rocksdb_compactionfilter_t() {
+  ~rocksdb_compactionfilter_t() override { (*destructor_)(state_); }
-    (*destructor_)(state_);
-  }
 
-  virtual bool Filter(int level, const Slice& key, const Slice& existing_value,
+  bool Filter(int level, const Slice& key, const Slice& existing_value,
-                      std::string* new_value,
+              std::string* new_value, bool* value_changed) const override {
-                      bool* value_changed) const override {
     char* c_new_value = nullptr;
     size_t new_value_length = 0;
     unsigned char c_value_changed = 0;
@@ -231,9 +228,9 @@ struct rocksdb_compactionfilter_t : public CompactionFilter {
     return result;
   }
 
-  virtual const char* Name() const override { return (*name_)(state_); }
+  const char* Name() const override { return (*name_)(state_); }
 
-  virtual bool IgnoreSnapshots() const override { return ignore_snapshots_; }
+  bool IgnoreSnapshots() const override { return ignore_snapshots_; }
 };
 
 struct rocksdb_compactionfilterfactory_t : public CompactionFilterFactory {
@@ -243,9 +240,9 @@ struct rocksdb_compactionfilterfactory_t : public CompactionFilterFactory {
       void*, rocksdb_compactionfiltercontext_t* context);
   const char* (*name_)(void*);
 
-  virtual ~rocksdb_compactionfilterfactory_t() { (*destructor_)(state_); }
+  ~rocksdb_compactionfilterfactory_t() override { (*destructor_)(state_); }
 
-  virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
+  std::unique_ptr<CompactionFilter> CreateCompactionFilter(
       const CompactionFilter::Context& context) override {
     rocksdb_compactionfiltercontext_t ccontext;
     ccontext.rep = context;
@@ -253,7 +250,7 @@ struct rocksdb_compactionfilterfactory_t : public CompactionFilterFactory {
     return std::unique_ptr<CompactionFilter>(cf);
   }
 
-  virtual const char* Name() const override { return (*name_)(state_); }
+  const char* Name() const override { return (*name_)(state_); }
 };
 
 struct rocksdb_comparator_t : public Comparator {
@@ -265,20 +262,17 @@ struct rocksdb_comparator_t : public Comparator {
       const char* b, size_t blen);
   const char* (*name_)(void*);
 
-  virtual ~rocksdb_comparator_t() {
+  ~rocksdb_comparator_t() override { (*destructor_)(state_); }
-    (*destructor_)(state_);
-  }
 
-  virtual int Compare(const Slice& a, const Slice& b) const override {
+  int Compare(const Slice& a, const Slice& b) const override {
     return (*compare_)(state_, a.data(), a.size(), b.data(), b.size());
   }
 
-  virtual const char* Name() const override { return (*name_)(state_); }
+  const char* Name() const override { return (*name_)(state_); }
 
   // No-ops since the C binding does not support key shortening methods.
-  virtual void FindShortestSeparator(std::string*,
+  void FindShortestSeparator(std::string*, const Slice&) const override {}
-                                     const Slice&) const override {}
+  void FindShortSuccessor(std::string* /*key*/) const override {}
-  virtual void FindShortSuccessor(std::string* /*key*/) const override {}
 };
 
 struct rocksdb_filterpolicy_t : public FilterPolicy {
@@ -298,14 +292,11 @@ struct rocksdb_filterpolicy_t : public FilterPolicy {
       void*,
       const char* filter, size_t filter_length);
 
-  virtual ~rocksdb_filterpolicy_t() {
+  ~rocksdb_filterpolicy_t() override { (*destructor_)(state_); }
-    (*destructor_)(state_);
-  }
 
-  virtual const char* Name() const override { return (*name_)(state_); }
+  const char* Name() const override { return (*name_)(state_); }
 
-  virtual void CreateFilter(const Slice* keys, int n,
+  void CreateFilter(const Slice* keys, int n, std::string* dst) const override {
-                            std::string* dst) const override {
     std::vector<const char*> key_pointers(n);
     std::vector<size_t> key_sizes(n);
     for (int i = 0; i < n; i++) {
@@ -323,8 +314,7 @@ struct rocksdb_filterpolicy_t : public FilterPolicy {
     }
   }
 
-  virtual bool KeyMayMatch(const Slice& key,
+  bool KeyMayMatch(const Slice& key, const Slice& filter) const override {
-                           const Slice& filter) const override {
     return (*key_match_)(state_, key.data(), key.size(),
                          filter.data(), filter.size());
   }
@@ -349,14 +339,12 @@ struct rocksdb_mergeoperator_t : public MergeOperator {
       void*,
       const char* value, size_t value_length);
 
-  virtual ~rocksdb_mergeoperator_t() {
+  ~rocksdb_mergeoperator_t() override { (*destructor_)(state_); }
-    (*destructor_)(state_);
-  }
 
-  virtual const char* Name() const override { return (*name_)(state_); }
+  const char* Name() const override { return (*name_)(state_); }
 
-  virtual bool FullMergeV2(const MergeOperationInput& merge_in,
+  bool FullMergeV2(const MergeOperationInput& merge_in,
-                           MergeOperationOutput* merge_out) const override {
+                   MergeOperationOutput* merge_out) const override {
     size_t n = merge_in.operand_list.size();
     std::vector<const char*> operand_pointers(n);
     std::vector<size_t> operand_sizes(n);
@@ -390,10 +378,10 @@ struct rocksdb_mergeoperator_t : public MergeOperator {
     return success;
   }
 
-  virtual bool PartialMergeMulti(const Slice& key,
+  bool PartialMergeMulti(const Slice& key,
-                                 const std::deque<Slice>& operand_list,
+                         const std::deque<Slice>& operand_list,
-                                 std::string* new_value,
+                         std::string* new_value,
-                                 Logger* /*logger*/) const override {
+                         Logger* /*logger*/) const override {
     size_t operand_count = operand_list.size();
     std::vector<const char*> operand_pointers(operand_count);
     std::vector<size_t> operand_sizes(operand_count);
@@ -444,23 +432,21 @@ struct rocksdb_slicetransform_t : public SliceTransform {
       void*,
       const char* key, size_t length);
 
-  virtual ~rocksdb_slicetransform_t() {
+  ~rocksdb_slicetransform_t() override { (*destructor_)(state_); }
-    (*destructor_)(state_);
-  }
 
-  virtual const char* Name() const override { return (*name_)(state_); }
+  const char* Name() const override { return (*name_)(state_); }
 
-  virtual Slice Transform(const Slice& src) const override {
+  Slice Transform(const Slice& src) const override {
     size_t len;
     char* dst = (*transform_)(state_, src.data(), src.size(), &len);
     return Slice(dst, len);
   }
 
-  virtual bool InDomain(const Slice& src) const override {
+  bool InDomain(const Slice& src) const override {
     return (*in_domain_)(state_, src.data(), src.size());
   }
 
-  virtual bool InRange(const Slice& src) const override {
+  bool InRange(const Slice& src) const override {
     return (*in_range_)(state_, src.data(), src.size());
   }
 };
@@ -1495,10 +1481,10 @@ class H : public WriteBatch::Handler {
   void* state_;
   void (*put_)(void*, const char* k, size_t klen, const char* v, size_t vlen);
   void (*deleted_)(void*, const char* k, size_t klen);
-  virtual void Put(const Slice& key, const Slice& value) override {
+  void Put(const Slice& key, const Slice& value) override {
     (*put_)(state_, key.data(), key.size(), value.data(), value.size());
   }
-  virtual void Delete(const Slice& key) override {
+  void Delete(const Slice& key) override {
     (*deleted_)(state_, key.data(), key.size());
   }
 };
@@ -2966,7 +2952,7 @@ rocksdb_filterpolicy_t* rocksdb_filterpolicy_create_bloom_format(int bits_per_ke
   // supplied C functions.
   struct Wrapper : public rocksdb_filterpolicy_t {
     const FilterPolicy* rep_;
-    ~Wrapper() { delete rep_; }
+    ~Wrapper() override { delete rep_; }
     const char* Name() const override { return rep_->Name(); }
     void CreateFilter(const Slice* keys, int n,
                       std::string* dst) const override {
@@ -3421,7 +3407,7 @@ void rocksdb_slicetransform_destroy(rocksdb_slicetransform_t* st) {
 
 struct Wrapper : public rocksdb_slicetransform_t {
   const SliceTransform* rep_;
-  ~Wrapper() { delete rep_; }
+  ~Wrapper() override { delete rep_; }
   const char* Name() const override { return rep_->Name(); }
   Slice Transform(const Slice& src) const override {
     return rep_->Transform(src);

db/column_family_test.cc

@@ -69,7 +69,7 @@ class ColumnFamilyTestBase : public testing::Test {
     DestroyDB(dbname_, Options(db_options_, column_family_options_));
   }
 
-  virtual ~ColumnFamilyTestBase() {
+  ~ColumnFamilyTestBase() override {
     std::vector<ColumnFamilyDescriptor> column_families;
     for (auto h : handles_) {
       ColumnFamilyDescriptor cfdescriptor;

db/compact_files_test.cc

@@ -35,9 +35,9 @@ class CompactFilesTest : public testing::Test {
 class FlushedFileCollector : public EventListener {
  public:
   FlushedFileCollector() {}
-  ~FlushedFileCollector() {}
+  ~FlushedFileCollector() override {}
 
-  virtual void OnFlushCompleted(DB* /*db*/, const FlushJobInfo& info) override {
+  void OnFlushCompleted(DB* /*db*/, const FlushJobInfo& info) override {
     std::lock_guard<std::mutex> lock(mutex_);
     flushed_files_.push_back(info.file_path);
   }
@@ -256,9 +256,9 @@ TEST_F(CompactFilesTest, CapturingPendingFiles) {
 TEST_F(CompactFilesTest, CompactionFilterWithGetSv) {
   class FilterWithGet : public CompactionFilter {
    public:
-    virtual bool Filter(int /*level*/, const Slice& /*key*/,
+    bool Filter(int /*level*/, const Slice& /*key*/, const Slice& /*value*/,
-                        const Slice& /*value*/, std::string* /*new_value*/,
+                std::string* /*new_value*/,
-                        bool* /*value_changed*/) const override {
+                bool* /*value_changed*/) const override {
       if (db_ == nullptr) {
         return true;
       }
@@ -271,7 +271,7 @@ TEST_F(CompactFilesTest, CompactionFilterWithGetSv) {
       db_ = db;
     }
 
-    virtual const char* Name() const override { return "FilterWithGet"; }
+    const char* Name() const override { return "FilterWithGet"; }
 
    private:
     DB* db_;

db/compaction_iterator_test.cc

@@ -112,39 +112,39 @@ class LoggingForwardVectorIterator : public InternalIterator {
     assert(keys_.size() == values_.size());
   }
 
-  virtual bool Valid() const override { return current_ < keys_.size(); }
+  bool Valid() const override { return current_ < keys_.size(); }
 
-  virtual void SeekToFirst() override {
+  void SeekToFirst() override {
     log.emplace_back(Action::Type::SEEK_TO_FIRST);
     current_ = 0;
   }
-  virtual void SeekToLast() override { assert(false); }
+  void SeekToLast() override { assert(false); }
 
-  virtual void Seek(const Slice& target) override {
+  void Seek(const Slice& target) override {
     log.emplace_back(Action::Type::SEEK, target.ToString());
     current_ = std::lower_bound(keys_.begin(), keys_.end(), target.ToString()) -
                keys_.begin();
   }
 
-  virtual void SeekForPrev(const Slice& /*target*/) override { assert(false); }
+  void SeekForPrev(const Slice& /*target*/) override { assert(false); }
 
-  virtual void Next() override {
+  void Next() override {
     assert(Valid());
     log.emplace_back(Action::Type::NEXT);
     current_++;
   }
-  virtual void Prev() override { assert(false); }
+  void Prev() override { assert(false); }
 
-  virtual Slice key() const override {
+  Slice key() const override {
     assert(Valid());
     return Slice(keys_[current_]);
   }
-  virtual Slice value() const override {
+  Slice value() const override {
     assert(Valid());
     return Slice(values_[current_]);
   }
 
-  virtual Status status() const override { return Status::OK(); }
+  Status status() const override { return Status::OK(); }
 
   std::vector<Action> log;
 
@@ -158,22 +158,20 @@ class FakeCompaction : public CompactionIterator::CompactionProxy {
  public:
   FakeCompaction() = default;
 
-  virtual int level(size_t /*compaction_input_level*/) const override {
+  int level(size_t /*compaction_input_level*/) const override { return 0; }
-    return 0;
+  bool KeyNotExistsBeyondOutputLevel(
-  }
-  virtual bool KeyNotExistsBeyondOutputLevel(
       const Slice& /*user_key*/,
       std::vector<size_t>* /*level_ptrs*/) const override {
     return is_bottommost_level || key_not_exists_beyond_output_level;
   }
-  virtual bool bottommost_level() const override { return is_bottommost_level; }
+  bool bottommost_level() const override { return is_bottommost_level; }
-  virtual int number_levels() const override { return 1; }
+  int number_levels() const override { return 1; }
-  virtual Slice GetLargestUserKey() const override {
+  Slice GetLargestUserKey() const override {
     return "\xff\xff\xff\xff\xff\xff\xff\xff\xff";
   }
-  virtual bool allow_ingest_behind() const override { return false; }
+  bool allow_ingest_behind() const override { return false; }
 
-  virtual bool preserve_deletes() const override { return false; }
+  bool preserve_deletes() const override { return false; }
 
   bool key_not_exists_beyond_output_level = false;
 
@@ -377,10 +375,9 @@ TEST_P(CompactionIteratorTest, RangeDeletionWithSnapshots) {
 
 TEST_P(CompactionIteratorTest, CompactionFilterSkipUntil) {
   class Filter : public CompactionFilter {
-    virtual Decision FilterV2(int /*level*/, const Slice& key, ValueType t,
+    Decision FilterV2(int /*level*/, const Slice& key, ValueType t,
-                              const Slice& existing_value,
+                      const Slice& existing_value, std::string* /*new_value*/,
-                              std::string* /*new_value*/,
+                      std::string* skip_until) const override {
-                              std::string* skip_until) const override {
       std::string k = key.ToString();
       std::string v = existing_value.ToString();
       // See InitIterators() call below for the sequence of keys and their
@@ -560,10 +557,9 @@ TEST_P(CompactionIteratorTest, ShuttingDownInMerge) {
 
 TEST_P(CompactionIteratorTest, SingleMergeOperand) {
   class Filter : public CompactionFilter {
-    virtual Decision FilterV2(int /*level*/, const Slice& key, ValueType t,
+    Decision FilterV2(int /*level*/, const Slice& key, ValueType t,
-                              const Slice& existing_value,
+                      const Slice& existing_value, std::string* /*new_value*/,
-                              std::string* /*new_value*/,
+                      std::string* /*skip_until*/) const override {
-                              std::string* /*skip_until*/) const override {
       std::string k = key.ToString();
       std::string v = existing_value.ToString();
 

db/compaction_job_stats_test.cc

@@ -113,7 +113,7 @@ class CompactionJobStatsTest : public testing::Test,
     Reopen(options);
   }
 
-  ~CompactionJobStatsTest() {
+  ~CompactionJobStatsTest() override {
     rocksdb::SyncPoint::GetInstance()->DisableProcessing();
     rocksdb::SyncPoint::GetInstance()->LoadDependency({});
     rocksdb::SyncPoint::GetInstance()->ClearAllCallBacks();
@@ -426,7 +426,7 @@ class CompactionJobStatsChecker : public EventListener {
   // Once a compaction completed, this function will verify the returned
   // CompactionJobInfo with the oldest CompactionJobInfo added earlier
   // in "expected_stats_" which has not yet being used for verification.
-  virtual void OnCompactionCompleted(DB* /*db*/, const CompactionJobInfo& ci) {
+  void OnCompactionCompleted(DB* /*db*/, const CompactionJobInfo& ci) override {
     if (verify_next_comp_io_stats_) {
       ASSERT_GT(ci.stats.file_write_nanos, 0);
       ASSERT_GT(ci.stats.file_range_sync_nanos, 0);
@@ -523,7 +523,7 @@ class CompactionJobDeletionStatsChecker : public CompactionJobStatsChecker {
  public:
   // Verifies whether two CompactionJobStats match.
   void Verify(const CompactionJobStats& current_stats,
-              const CompactionJobStats& stats) {
+              const CompactionJobStats& stats) override {
     ASSERT_EQ(
       current_stats.num_input_deletion_records,
       stats.num_input_deletion_records);

db/compaction_picker_test.cc

@@ -22,9 +22,7 @@ namespace rocksdb {
 class CountingLogger : public Logger {
  public:
   using Logger::Logv;
-  virtual void Logv(const char* /*format*/, va_list /*ap*/) override {
+  void Logv(const char* /*format*/, va_list /*ap*/) override { log_count++; }
-    log_count++;
-  }
   size_t log_count;
 };
 
@@ -68,8 +66,7 @@ class CompactionPickerTest : public testing::Test {
                                     std::numeric_limits<uint64_t>::max());
   }
 
-  ~CompactionPickerTest() {
+  ~CompactionPickerTest() override {}
-  }
 
   void NewVersionStorage(int num_levels, CompactionStyle style) {
     DeleteVersionStorage();

db/comparator_db_test.cc

@@ -27,24 +27,24 @@ class KVIter : public Iterator {
  public:
   explicit KVIter(const stl_wrappers::KVMap* map)
       : map_(map), iter_(map_->end()) {}
-  virtual bool Valid() const override { return iter_ != map_->end(); }
+  bool Valid() const override { return iter_ != map_->end(); }
-  virtual void SeekToFirst() override { iter_ = map_->begin(); }
+  void SeekToFirst() override { iter_ = map_->begin(); }
-  virtual void SeekToLast() override {
+  void SeekToLast() override {
     if (map_->empty()) {
       iter_ = map_->end();
     } else {
       iter_ = map_->find(map_->rbegin()->first);
     }
   }
-  virtual void Seek(const Slice& k) override {
+  void Seek(const Slice& k) override {
     iter_ = map_->lower_bound(k.ToString());
   }
-  virtual void SeekForPrev(const Slice& k) override {
+  void SeekForPrev(const Slice& k) override {
     iter_ = map_->upper_bound(k.ToString());
     Prev();
   }
-  virtual void Next() override { ++iter_; }
+  void Next() override { ++iter_; }
-  virtual void Prev() override {
+  void Prev() override {
     if (iter_ == map_->begin()) {
       iter_ = map_->end();
       return;
@@ -52,9 +52,9 @@ class KVIter : public Iterator {
     --iter_;
   }
 
-  virtual Slice key() const override { return iter_->first; }
+  Slice key() const override { return iter_->first; }
-  virtual Slice value() const override { return iter_->second; }
+  Slice value() const override { return iter_->second; }
-  virtual Status status() const override { return Status::OK(); }
+  Status status() const override { return Status::OK(); }
 
  private:
   const stl_wrappers::KVMap* const map_;
@@ -171,9 +171,9 @@ class DoubleComparator : public Comparator {
  public:
   DoubleComparator() {}
 
-  virtual const char* Name() const override { return "DoubleComparator"; }
+  const char* Name() const override { return "DoubleComparator"; }
 
-  virtual int Compare(const Slice& a, const Slice& b) const override {
+  int Compare(const Slice& a, const Slice& b) const override {
 #ifndef CYGWIN
     double da = std::stod(a.ToString());
     double db = std::stod(b.ToString());
@@ -189,19 +189,19 @@ class DoubleComparator : public Comparator {
       return -1;
     }
   }
-  virtual void FindShortestSeparator(std::string* /*start*/,
+  void FindShortestSeparator(std::string* /*start*/,
-                                     const Slice& /*limit*/) const override {}
+                             const Slice& /*limit*/) const override {}
 
-  virtual void FindShortSuccessor(std::string* /*key*/) const override {}
+  void FindShortSuccessor(std::string* /*key*/) const override {}
 };
 
 class HashComparator : public Comparator {
  public:
   HashComparator() {}
 
-  virtual const char* Name() const override { return "HashComparator"; }
+  const char* Name() const override { return "HashComparator"; }
 
-  virtual int Compare(const Slice& a, const Slice& b) const override {
+  int Compare(const Slice& a, const Slice& b) const override {
     uint32_t ha = Hash(a.data(), a.size(), 66);
     uint32_t hb = Hash(b.data(), b.size(), 66);
     if (ha == hb) {
@@ -212,19 +212,19 @@ class HashComparator : public Comparator {
       return -1;
     }
   }
-  virtual void FindShortestSeparator(std::string* /*start*/,
+  void FindShortestSeparator(std::string* /*start*/,
-                                     const Slice& /*limit*/) const override {}
+                             const Slice& /*limit*/) const override {}
 
-  virtual void FindShortSuccessor(std::string* /*key*/) const override {}
+  void FindShortSuccessor(std::string* /*key*/) const override {}
 };
 
 class TwoStrComparator : public Comparator {
  public:
   TwoStrComparator() {}
 
-  virtual const char* Name() const override { return "TwoStrComparator"; }
+  const char* Name() const override { return "TwoStrComparator"; }
 
-  virtual int Compare(const Slice& a, const Slice& b) const override {
+  int Compare(const Slice& a, const Slice& b) const override {
     assert(a.size() >= 2);
     assert(b.size() >= 2);
     size_t size_a1 = static_cast<size_t>(a[0]);
@@ -244,10 +244,10 @@ class TwoStrComparator : public Comparator {
     }
     return a2.compare(b2);
   }
-  virtual void FindShortestSeparator(std::string* /*start*/,
+  void FindShortestSeparator(std::string* /*start*/,
-                                     const Slice& /*limit*/) const override {}
+                             const Slice& /*limit*/) const override {}
 
-  virtual void FindShortSuccessor(std::string* /*key*/) const override {}
+  void FindShortSuccessor(std::string* /*key*/) const override {}
 };
 }  // namespace
 
@@ -272,7 +272,7 @@ class ComparatorDBTest
     EXPECT_OK(DestroyDB(dbname_, last_options_));
   }
 
-  ~ComparatorDBTest() {
+  ~ComparatorDBTest() override {
     delete db_;
     EXPECT_OK(DestroyDB(dbname_, last_options_));
     comparator = BytewiseComparator();

db/corruption_test.cc

@@ -62,9 +62,9 @@ class CorruptionTest : public testing::Test {
     options_.create_if_missing = false;
   }
 
-  ~CorruptionTest() {
+  ~CorruptionTest() override {
-     delete db_;
+    delete db_;
-     DestroyDB(dbname_, Options());
+    DestroyDB(dbname_, Options());
   }
 
   void CloseDb() {

db/cuckoo_table_db_test.cc

@@ -31,7 +31,7 @@ class CuckooTableDBTest : public testing::Test {
     Reopen();
   }
 
-  ~CuckooTableDBTest() {
+  ~CuckooTableDBTest() override {
     delete db_;
     EXPECT_OK(DestroyDB(dbname_, Options()));
   }

db/db_basic_test.cc

@@ -852,18 +852,17 @@ class TestEnv : public EnvWrapper {
       public:
         using Logger::Logv;
         TestLogger(TestEnv *env_ptr) : Logger() { env = env_ptr; }
-        ~TestLogger() {
+        ~TestLogger() override {
           if (!closed_) {
             CloseHelper();
           }
         }
-        virtual void Logv(const char* /*format*/, va_list /*ap*/) override{};
+        void Logv(const char* /*format*/, va_list /*ap*/) override{};
 
        protected:
-        virtual Status CloseImpl() override {
+        Status CloseImpl() override { return CloseHelper(); }
-          return CloseHelper();
+
-        }
+       private:
-      private:
         Status CloseHelper() {
           env->CloseCountInc();;
           return Status::IOError();
@@ -875,8 +874,8 @@ class TestEnv : public EnvWrapper {
 
     int GetCloseCount() { return close_count; }
 
-    virtual Status NewLogger(const std::string& /*fname*/,
+    Status NewLogger(const std::string& /*fname*/,
-                             std::shared_ptr<Logger>* result) {
+                     std::shared_ptr<Logger>* result) override {
       result->reset(new TestLogger(this));
       return Status::OK();
     }

db/db_block_cache_test.cc

@@ -395,9 +395,9 @@ class MockCache : public LRUCache {
                  false /*strict_capacity_limit*/, 0.0 /*high_pri_pool_ratio*/) {
   }
 
-  virtual Status Insert(const Slice& key, void* value, size_t charge,
+  Status Insert(const Slice& key, void* value, size_t charge,
-                        void (*deleter)(const Slice& key, void* value),
+                void (*deleter)(const Slice& key, void* value), Handle** handle,
-                        Handle** handle, Priority priority) override {
+                Priority priority) override {
     if (priority == Priority::LOW) {
       low_pri_insert_count++;
     } else {

db/db_bloom_filter_test.cc

@@ -32,7 +32,7 @@ class DBBloomFilterTestWithParam
  public:
   DBBloomFilterTestWithParam() : DBTestBase("/db_bloom_filter_tests") {}
 
-  ~DBBloomFilterTestWithParam() {}
+  ~DBBloomFilterTestWithParam() override {}
 
   void SetUp() override {
     use_block_based_filter_ = std::get<0>(GetParam());
@@ -642,7 +642,7 @@ class WrappedBloom : public FilterPolicy {
   explicit WrappedBloom(int bits_per_key)
       : filter_(NewBloomFilterPolicy(bits_per_key)), counter_(0) {}
 
-  ~WrappedBloom() { delete filter_; }
+  ~WrappedBloom() override { delete filter_; }
 
   const char* Name() const override { return "WrappedRocksDbFilterPolicy"; }
 
@@ -823,7 +823,7 @@ class BloomStatsTestWithParam
     DestroyAndReopen(options_);
   }
 
-  ~BloomStatsTestWithParam() {
+  ~BloomStatsTestWithParam() override {
     get_perf_context()->Reset();
     Destroy(options_);
   }

db/db_compaction_filter_test.cc

@@ -63,33 +63,33 @@ INSTANTIATE_TEST_CASE_P(DBTestCompactionFilterWithCompactOption,
 
 class KeepFilter : public CompactionFilter {
  public:
-  virtual bool Filter(int /*level*/, const Slice& /*key*/,
+  bool Filter(int /*level*/, const Slice& /*key*/, const Slice& /*value*/,
-                      const Slice& /*value*/, std::string* /*new_value*/,
+              std::string* /*new_value*/,
-                      bool* /*value_changed*/) const override {
+              bool* /*value_changed*/) const override {
     cfilter_count++;
     return false;
   }
 
-  virtual const char* Name() const override { return "KeepFilter"; }
+  const char* Name() const override { return "KeepFilter"; }
 };
 
 class DeleteFilter : public CompactionFilter {
  public:
-  virtual bool Filter(int /*level*/, const Slice& /*key*/,
+  bool Filter(int /*level*/, const Slice& /*key*/, const Slice& /*value*/,
-                      const Slice& /*value*/, std::string* /*new_value*/,
+              std::string* /*new_value*/,
-                      bool* /*value_changed*/) const override {
+              bool* /*value_changed*/) const override {
     cfilter_count++;
     return true;
   }
 
-  virtual const char* Name() const override { return "DeleteFilter"; }
+  const char* Name() const override { return "DeleteFilter"; }
 };
 
 class DeleteISFilter : public CompactionFilter {
  public:
-  virtual bool Filter(int /*level*/, const Slice& key, const Slice& /*value*/,
+  bool Filter(int /*level*/, const Slice& key, const Slice& /*value*/,
-                      std::string* /*new_value*/,
+              std::string* /*new_value*/,
-                      bool* /*value_changed*/) const override {
+              bool* /*value_changed*/) const override {
     cfilter_count++;
     int i = std::stoi(key.ToString());
     if (i > 5 && i <= 105) {
@@ -98,20 +98,18 @@ class DeleteISFilter : public CompactionFilter {
     return false;
   }
 
-  virtual bool IgnoreSnapshots() const override { return true; }
+  bool IgnoreSnapshots() const override { return true; }
 
-  virtual const char* Name() const override { return "DeleteFilter"; }
+  const char* Name() const override { return "DeleteFilter"; }
 };
 
 // Skip x if floor(x/10) is even, use range skips. Requires that keys are
 // zero-padded to length 10.
 class SkipEvenFilter : public CompactionFilter {
  public:
-  virtual Decision FilterV2(int /*level*/, const Slice& key,
+  Decision FilterV2(int /*level*/, const Slice& key, ValueType /*value_type*/,
-                            ValueType /*value_type*/,
+                    const Slice& /*existing_value*/, std::string* /*new_value*/,
-                            const Slice& /*existing_value*/,
+                    std::string* skip_until) const override {
-                            std::string* /*new_value*/,
-                            std::string* skip_until) const override {
     cfilter_count++;
     int i = std::stoi(key.ToString());
     if (i / 10 % 2 == 0) {
@@ -124,22 +122,22 @@ class SkipEvenFilter : public CompactionFilter {
     return Decision::kKeep;
   }
 
-  virtual bool IgnoreSnapshots() const override { return true; }
+  bool IgnoreSnapshots() const override { return true; }
 
-  virtual const char* Name() const override { return "DeleteFilter"; }
+  const char* Name() const override { return "DeleteFilter"; }
 };
 
 class DelayFilter : public CompactionFilter {
  public:
   explicit DelayFilter(DBTestBase* d) : db_test(d) {}
-  virtual bool Filter(int /*level*/, const Slice& /*key*/,
+  bool Filter(int /*level*/, const Slice& /*key*/, const Slice& /*value*/,
-                      const Slice& /*value*/, std::string* /*new_value*/,
+              std::string* /*new_value*/,
-                      bool* /*value_changed*/) const override {
+              bool* /*value_changed*/) const override {
     db_test->env_->addon_time_.fetch_add(1000);
     return true;
   }
 
-  virtual const char* Name() const override { return "DelayFilter"; }
+  const char* Name() const override { return "DelayFilter"; }
 
  private:
   DBTestBase* db_test;
@@ -149,13 +147,13 @@ class ConditionalFilter : public CompactionFilter {
  public:
   explicit ConditionalFilter(const std::string* filtered_value)
       : filtered_value_(filtered_value) {}
-  virtual bool Filter(int /*level*/, const Slice& /*key*/, const Slice& value,
+  bool Filter(int /*level*/, const Slice& /*key*/, const Slice& value,
-                      std::string* /*new_value*/,
+              std::string* /*new_value*/,
-                      bool* /*value_changed*/) const override {
+              bool* /*value_changed*/) const override {
     return value.ToString() == *filtered_value_;
   }
 
-  virtual const char* Name() const override { return "ConditionalFilter"; }
+  const char* Name() const override { return "ConditionalFilter"; }
 
  private:
   const std::string* filtered_value_;
@@ -165,16 +163,15 @@ class ChangeFilter : public CompactionFilter {
  public:
   explicit ChangeFilter() {}
 
-  virtual bool Filter(int /*level*/, const Slice& /*key*/,
+  bool Filter(int /*level*/, const Slice& /*key*/, const Slice& /*value*/,
-                      const Slice& /*value*/, std::string* new_value,
+              std::string* new_value, bool* value_changed) const override {
-                      bool* value_changed) const override {
     assert(new_value != nullptr);
     *new_value = NEW_VALUE;
     *value_changed = true;
     return false;
   }
 
-  virtual const char* Name() const override { return "ChangeFilter"; }
+  const char* Name() const override { return "ChangeFilter"; }
 };
 
 class KeepFilterFactory : public CompactionFilterFactory {
@@ -185,7 +182,7 @@ class KeepFilterFactory : public CompactionFilterFactory {
         check_context_cf_id_(check_context_cf_id),
         compaction_filter_created_(false) {}
 
-  virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
+  std::unique_ptr<CompactionFilter> CreateCompactionFilter(
       const CompactionFilter::Context& context) override {
     if (check_context_) {
       EXPECT_EQ(expect_full_compaction_.load(), context.is_full_compaction);
@@ -200,7 +197,7 @@ class KeepFilterFactory : public CompactionFilterFactory {
 
   bool compaction_filter_created() const { return compaction_filter_created_; }
 
-  virtual const char* Name() const override { return "KeepFilterFactory"; }
+  const char* Name() const override { return "KeepFilterFactory"; }
   bool check_context_;
   bool check_context_cf_id_;
   std::atomic_bool expect_full_compaction_;
@@ -211,7 +208,7 @@ class KeepFilterFactory : public CompactionFilterFactory {
 
 class DeleteFilterFactory : public CompactionFilterFactory {
  public:
-  virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
+  std::unique_ptr<CompactionFilter> CreateCompactionFilter(
       const CompactionFilter::Context& context) override {
     if (context.is_manual_compaction) {
       return std::unique_ptr<CompactionFilter>(new DeleteFilter());
@@ -220,13 +217,13 @@ class DeleteFilterFactory : public CompactionFilterFactory {
     }
   }
 
-  virtual const char* Name() const override { return "DeleteFilterFactory"; }
+  const char* Name() const override { return "DeleteFilterFactory"; }
 };
 
 // Delete Filter Factory which ignores snapshots
 class DeleteISFilterFactory : public CompactionFilterFactory {
  public:
-  virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
+  std::unique_ptr<CompactionFilter> CreateCompactionFilter(
       const CompactionFilter::Context& context) override {
     if (context.is_manual_compaction) {
       return std::unique_ptr<CompactionFilter>(new DeleteISFilter());
@@ -235,12 +232,12 @@ class DeleteISFilterFactory : public CompactionFilterFactory {
     }
   }
 
-  virtual const char* Name() const override { return "DeleteFilterFactory"; }
+  const char* Name() const override { return "DeleteFilterFactory"; }
 };
 
 class SkipEvenFilterFactory : public CompactionFilterFactory {
  public:
-  virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
+  std::unique_ptr<CompactionFilter> CreateCompactionFilter(
       const CompactionFilter::Context& context) override {
     if (context.is_manual_compaction) {
       return std::unique_ptr<CompactionFilter>(new SkipEvenFilter());
@@ -249,18 +246,18 @@ class SkipEvenFilterFactory : public CompactionFilterFactory {
     }
   }
 
-  virtual const char* Name() const override { return "SkipEvenFilterFactory"; }
+  const char* Name() const override { return "SkipEvenFilterFactory"; }
 };
 
 class DelayFilterFactory : public CompactionFilterFactory {
  public:
   explicit DelayFilterFactory(DBTestBase* d) : db_test(d) {}
-  virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
+  std::unique_ptr<CompactionFilter> CreateCompactionFilter(
       const CompactionFilter::Context& /*context*/) override {
     return std::unique_ptr<CompactionFilter>(new DelayFilter(db_test));
   }
 
-  virtual const char* Name() const override { return "DelayFilterFactory"; }
+  const char* Name() const override { return "DelayFilterFactory"; }
 
  private:
   DBTestBase* db_test;
@@ -271,15 +268,13 @@ class ConditionalFilterFactory : public CompactionFilterFactory {
   explicit ConditionalFilterFactory(const Slice& filtered_value)
       : filtered_value_(filtered_value.ToString()) {}
 
-  virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
+  std::unique_ptr<CompactionFilter> CreateCompactionFilter(
       const CompactionFilter::Context& /*context*/) override {
     return std::unique_ptr<CompactionFilter>(
         new ConditionalFilter(&filtered_value_));
   }
 
-  virtual const char* Name() const override {
+  const char* Name() const override { return "ConditionalFilterFactory"; }
-    return "ConditionalFilterFactory";
-  }
 
  private:
   std::string filtered_value_;
@@ -289,12 +284,12 @@ class ChangeFilterFactory : public CompactionFilterFactory {
  public:
   explicit ChangeFilterFactory() {}
 
-  virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
+  std::unique_ptr<CompactionFilter> CreateCompactionFilter(
       const CompactionFilter::Context& /*context*/) override {
     return std::unique_ptr<CompactionFilter>(new ChangeFilter());
   }
 
-  virtual const char* Name() const override { return "ChangeFilterFactory"; }
+  const char* Name() const override { return "ChangeFilterFactory"; }
 };
 
 #ifndef ROCKSDB_LITE
@@ -845,7 +840,7 @@ class TestNotSupportedFilter : public CompactionFilter {
     return true;
   }
 
-  virtual const char* Name() const override { return "NotSupported"; }
+  const char* Name() const override { return "NotSupported"; }
   bool IgnoreSnapshots() const override { return false; }
 };
 

db/db_compaction_test.cc

@@ -55,9 +55,9 @@ namespace {
 class FlushedFileCollector : public EventListener {
  public:
   FlushedFileCollector() {}
-  ~FlushedFileCollector() {}
+  ~FlushedFileCollector() override {}
 
-  virtual void OnFlushCompleted(DB* /*db*/, const FlushJobInfo& info) override {
+  void OnFlushCompleted(DB* /*db*/, const FlushJobInfo& info) override {
     std::lock_guard<std::mutex> lock(mutex_);
     flushed_files_.push_back(info.file_path);
   }
@@ -87,24 +87,23 @@ public:
     }
   }
 
-  ~CompactionStatsCollector() {}
+  ~CompactionStatsCollector() override {}
 
-  virtual void OnCompactionCompleted(DB* /* db */,
+  void OnCompactionCompleted(DB* /* db */,
-      const CompactionJobInfo& info) override {
+                             const CompactionJobInfo& info) override {
     int k = static_cast<int>(info.compaction_reason);
     int num_of_reasons = static_cast<int>(CompactionReason::kNumOfReasons);
     assert(k >= 0 && k < num_of_reasons);
     compaction_completed_[k]++;
   }
 
-  virtual void OnExternalFileIngested(DB* /* db */,
+  void OnExternalFileIngested(
-      const ExternalFileIngestionInfo& /* info */) override {
+      DB* /* db */, const ExternalFileIngestionInfo& /* info */) override {
     int k = static_cast<int>(CompactionReason::kExternalSstIngestion);
     compaction_completed_[k]++;
   }
 
-  virtual void OnFlushCompleted(DB* /* db */,
+  void OnFlushCompleted(DB* /* db */, const FlushJobInfo& /* info */) override {
-      const FlushJobInfo& /* info */) override {
     int k = static_cast<int>(CompactionReason::kFlush);
     compaction_completed_[k]++;
   }
@@ -4187,14 +4186,14 @@ class NoopMergeOperator : public MergeOperator {
  public:
   NoopMergeOperator() {}
 
-  virtual bool FullMergeV2(const MergeOperationInput& /*merge_in*/,
+  bool FullMergeV2(const MergeOperationInput& /*merge_in*/,
-                           MergeOperationOutput* merge_out) const override {
+                   MergeOperationOutput* merge_out) const override {
     std::string val("bar");
     merge_out->new_value = val;
     return true;
   }
 
-  virtual const char* Name() const override { return "Noop"; }
+  const char* Name() const override { return "Noop"; }
 };
 
 TEST_F(DBCompactionTest, PartialManualCompaction) {

db/db_impl_open.cc

@@ -512,7 +512,7 @@ Status DBImpl::RecoverLogFiles(const std::vector<uint64_t>& log_numbers,
     Logger* info_log;
     const char* fname;
     Status* status;  // nullptr if immutable_db_options_.paranoid_checks==false
-    virtual void Corruption(size_t bytes, const Status& s) override {
+    void Corruption(size_t bytes, const Status& s) override {
       ROCKS_LOG_WARN(info_log, "%s%s: dropping %d bytes; %s",
                      (this->status == nullptr ? "(ignoring error) " : ""),
                      fname, static_cast<int>(bytes), s.ToString().c_str());

db/db_iter.cc

@@ -152,7 +152,7 @@ class DBIter final: public Iterator {
       iter_->SetPinnedItersMgr(&pinned_iters_mgr_);
     }
   }
-  virtual ~DBIter() {
+  ~DBIter() override {
     // Release pinned data if any
     if (pinned_iters_mgr_.PinningEnabled()) {
       pinned_iters_mgr_.ReleasePinnedData();
@@ -175,17 +175,16 @@ class DBIter final: public Iterator {
     return &range_del_agg_;
   }
 
-  virtual bool Valid() const override { return valid_; }
+  bool Valid() const override { return valid_; }
-  virtual Slice key() const override {
+  Slice key() const override {
     assert(valid_);
     if(start_seqnum_ > 0) {
       return saved_key_.GetInternalKey();
     } else {
       return saved_key_.GetUserKey();
     }
-
   }
-  virtual Slice value() const override {
+  Slice value() const override {
     assert(valid_);
     if (current_entry_is_merged_) {
       // If pinned_value_ is set then the result of merge operator is one of
@@ -197,7 +196,7 @@ class DBIter final: public Iterator {
       return iter_->value();
     }
   }
-  virtual Status status() const override {
+  Status status() const override {
     if (status_.ok()) {
       return iter_->status();
     } else {
@@ -210,8 +209,7 @@ class DBIter final: public Iterator {
     return is_blob_;
   }
 
-  virtual Status GetProperty(std::string prop_name,
+  Status GetProperty(std::string prop_name, std::string* prop) override {
-                             std::string* prop) override {
     if (prop == nullptr) {
       return Status::InvalidArgument("prop is nullptr");
     }
@@ -232,12 +230,12 @@ class DBIter final: public Iterator {
     return Status::InvalidArgument("Unidentified property.");
   }
 
-  virtual void Next() override;
+  void Next() override;
-  virtual void Prev() override;
+  void Prev() override;
-  virtual void Seek(const Slice& target) override;
+  void Seek(const Slice& target) override;
-  virtual void SeekForPrev(const Slice& target) override;
+  void SeekForPrev(const Slice& target) override;
-  virtual void SeekToFirst() override;
+  void SeekToFirst() override;
-  virtual void SeekToLast() override;
+  void SeekToLast() override;
   Env* env() { return env_; }
   void set_sequence(uint64_t s) { sequence_ = s; }
   void set_valid(bool v) { valid_ = v; }

db/db_iter_test.cc

@@ -116,12 +116,12 @@ class TestIterator : public InternalIterator {
   // Number of operations done on this iterator since construction.
   size_t steps() const { return steps_; }
 
-  virtual bool Valid() const override {
+  bool Valid() const override {
     assert(initialized_);
     return valid_;
   }
 
-  virtual void SeekToFirst() override {
+  void SeekToFirst() override {
     assert(initialized_);
     ++steps_;
     DeleteCurrentIfNeeded();
@@ -129,7 +129,7 @@ class TestIterator : public InternalIterator {
     iter_ = 0;
   }
 
-  virtual void SeekToLast() override {
+  void SeekToLast() override {
     assert(initialized_);
     ++steps_;
     DeleteCurrentIfNeeded();
@@ -137,7 +137,7 @@ class TestIterator : public InternalIterator {
     iter_ = data_.size() - 1;
   }
 
-  virtual void Seek(const Slice& target) override {
+  void Seek(const Slice& target) override {
     assert(initialized_);
     SeekToFirst();
     ++steps_;
@@ -154,13 +154,13 @@ class TestIterator : public InternalIterator {
     }
   }
 
-  virtual void SeekForPrev(const Slice& target) override {
+  void SeekForPrev(const Slice& target) override {
     assert(initialized_);
     DeleteCurrentIfNeeded();
     SeekForPrevImpl(target, &cmp);
   }
 
-  virtual void Next() override {
+  void Next() override {
     assert(initialized_);
     assert(valid_);
     assert(iter_ < data_.size());
@@ -174,7 +174,7 @@ class TestIterator : public InternalIterator {
     valid_ = iter_ < data_.size();
   }
 
-  virtual void Prev() override {
+  void Prev() override {
     assert(initialized_);
     assert(valid_);
     assert(iter_ < data_.size());
@@ -188,23 +188,23 @@ class TestIterator : public InternalIterator {
     }
   }
 
-  virtual Slice key() const override {
+  Slice key() const override {
     assert(initialized_);
     return data_[iter_].first;
   }
 
-  virtual Slice value() const override {
+  Slice value() const override {
     assert(initialized_);
     return data_[iter_].second;
   }
 
-  virtual Status status() const override {
+  Status status() const override {
     assert(initialized_);
     return Status::OK();
   }
 
-  virtual bool IsKeyPinned() const override { return true; }
+  bool IsKeyPinned() const override { return true; }
-  virtual bool IsValuePinned() const override { return true; }
+  bool IsValuePinned() const override { return true; }
 
  private:
   bool initialized_;

db/db_iterator_test.cc

@@ -50,13 +50,14 @@ class DBIteratorTest : public DBTestBase,
 
 class FlushBlockEveryKeyPolicy : public FlushBlockPolicy {
  public:
-  virtual bool Update(const Slice& /*key*/, const Slice& /*value*/) override {
+  bool Update(const Slice& /*key*/, const Slice& /*value*/) override {
     if (!start_) {
       start_ = true;
       return false;
     }
     return true;
   }
+
  private:
   bool start_ = false;
 };

db/db_log_iter_test.cc

@@ -249,22 +249,20 @@ TEST_F(DBTestXactLogIterator, TransactionLogIteratorBlobs) {
   auto res = OpenTransactionLogIter(0)->GetBatch();
   struct Handler : public WriteBatch::Handler {
     std::string seen;
-    virtual Status PutCF(uint32_t cf, const Slice& key,
+    Status PutCF(uint32_t cf, const Slice& key, const Slice& value) override {
-                         const Slice& value) override {
       seen += "Put(" + ToString(cf) + ", " + key.ToString() + ", " +
               ToString(value.size()) + ")";
       return Status::OK();
     }
-    virtual Status MergeCF(uint32_t cf, const Slice& key,
+    Status MergeCF(uint32_t cf, const Slice& key, const Slice& value) override {
-                           const Slice& value) override {
       seen += "Merge(" + ToString(cf) + ", " + key.ToString() + ", " +
               ToString(value.size()) + ")";
       return Status::OK();
     }
-    virtual void LogData(const Slice& blob) override {
+    void LogData(const Slice& blob) override {
       seen += "LogData(" + blob.ToString() + ")";
     }
-    virtual Status DeleteCF(uint32_t cf, const Slice& key) override {
+    Status DeleteCF(uint32_t cf, const Slice& key) override {
       seen += "Delete(" + ToString(cf) + ", " + key.ToString() + ")";
       return Status::OK();
     }

db/db_memtable_test.cc

@@ -25,13 +25,13 @@ class MockMemTableRep : public MemTableRep {
   explicit MockMemTableRep(Allocator* allocator, MemTableRep* rep)
       : MemTableRep(allocator), rep_(rep), num_insert_with_hint_(0) {}
 
-  virtual KeyHandle Allocate(const size_t len, char** buf) override {
+  KeyHandle Allocate(const size_t len, char** buf) override {
     return rep_->Allocate(len, buf);
   }
 
-  virtual void Insert(KeyHandle handle) override { rep_->Insert(handle); }
+  void Insert(KeyHandle handle) override { rep_->Insert(handle); }
 
-  virtual void InsertWithHint(KeyHandle handle, void** hint) override {
+  void InsertWithHint(KeyHandle handle, void** hint) override {
     num_insert_with_hint_++;
     EXPECT_NE(nullptr, hint);
     last_hint_in_ = *hint;
@@ -39,21 +39,18 @@ class MockMemTableRep : public MemTableRep {
     last_hint_out_ = *hint;
   }
 
-  virtual bool Contains(const char* key) const override {
+  bool Contains(const char* key) const override { return rep_->Contains(key); }
-    return rep_->Contains(key);
-  }
 
-  virtual void Get(const LookupKey& k, void* callback_args,
+  void Get(const LookupKey& k, void* callback_args,
-                   bool (*callback_func)(void* arg,
+           bool (*callback_func)(void* arg, const char* entry)) override {
-                                         const char* entry)) override {
     rep_->Get(k, callback_args, callback_func);
   }
 
-  virtual size_t ApproximateMemoryUsage() override {
+  size_t ApproximateMemoryUsage() override {
     return rep_->ApproximateMemoryUsage();
   }
 
-  virtual Iterator* GetIterator(Arena* arena) override {
+  Iterator* GetIterator(Arena* arena) override {
     return rep_->GetIterator(arena);
   }
 
@@ -70,10 +67,10 @@ class MockMemTableRep : public MemTableRep {
 
 class MockMemTableRepFactory : public MemTableRepFactory {
  public:
-  virtual MemTableRep* CreateMemTableRep(const MemTableRep::KeyComparator& cmp,
+  MemTableRep* CreateMemTableRep(const MemTableRep::KeyComparator& cmp,
-                                         Allocator* allocator,
+                                 Allocator* allocator,
-                                         const SliceTransform* transform,
+                                 const SliceTransform* transform,
-                                         Logger* logger) override {
+                                 Logger* logger) override {
     SkipListFactory factory;
     MemTableRep* skiplist_rep =
         factory.CreateMemTableRep(cmp, allocator, transform, logger);
@@ -81,16 +78,16 @@ class MockMemTableRepFactory : public MemTableRepFactory {
     return mock_rep_;
   }
 
-  virtual MemTableRep* CreateMemTableRep(const MemTableRep::KeyComparator& cmp,
+  MemTableRep* CreateMemTableRep(const MemTableRep::KeyComparator& cmp,
-                                         Allocator* allocator,
+                                 Allocator* allocator,
-                                         const SliceTransform* transform,
+                                 const SliceTransform* transform,
-                                         Logger* logger,
+                                 Logger* logger,
-                                         uint32_t column_family_id) override {
+                                 uint32_t column_family_id) override {
     last_column_family_id_ = column_family_id;
     return CreateMemTableRep(cmp, allocator, transform, logger);
   }
 
-  virtual const char* Name() const override { return "MockMemTableRepFactory"; }
+  const char* Name() const override { return "MockMemTableRepFactory"; }
 
   MockMemTableRep* rep() { return mock_rep_; }
 
@@ -106,9 +103,9 @@ class MockMemTableRepFactory : public MemTableRepFactory {
 
 class TestPrefixExtractor : public SliceTransform {
  public:
-  virtual const char* Name() const override { return "TestPrefixExtractor"; }
+  const char* Name() const override { return "TestPrefixExtractor"; }
 
-  virtual Slice Transform(const Slice& key) const override {
+  Slice Transform(const Slice& key) const override {
     const char* p = separator(key);
     if (p == nullptr) {
       return Slice();
@@ -116,11 +113,11 @@ class TestPrefixExtractor : public SliceTransform {
     return Slice(key.data(), p - key.data() + 1);
   }
 
-  virtual bool InDomain(const Slice& key) const override {
+  bool InDomain(const Slice& key) const override {
     return separator(key) != nullptr;
   }
 
-  virtual bool InRange(const Slice& /*key*/) const override { return false; }
+  bool InRange(const Slice& /*key*/) const override { return false; }
 
  private:
   const char* separator(const Slice& key) const {

db/db_merge_operator_test.cc

@@ -340,15 +340,15 @@ class MergeOperatorHook : public MergeOperator {
   explicit MergeOperatorHook(std::shared_ptr<MergeOperator> _merge_op)
       : merge_op_(_merge_op) {}
 
-  virtual bool FullMergeV2(const MergeOperationInput& merge_in,
+  bool FullMergeV2(const MergeOperationInput& merge_in,
-                           MergeOperationOutput* merge_out) const override {
+                   MergeOperationOutput* merge_out) const override {
     before_merge_();
     bool res = merge_op_->FullMergeV2(merge_in, merge_out);
     after_merge_();
     return res;
   }
 
-  virtual const char* Name() const override { return merge_op_->Name(); }
+  const char* Name() const override { return merge_op_->Name(); }
 
   std::shared_ptr<MergeOperator> merge_op_;
   std::function<void()> before_merge_ = []() {};

db/db_properties_test.cc

@@ -1094,7 +1094,7 @@ class CountingUserTblPropCollector : public TablePropertiesCollector {
     return Status::OK();
   }
 
-  virtual UserCollectedProperties GetReadableProperties() const override {
+  UserCollectedProperties GetReadableProperties() const override {
     return UserCollectedProperties{};
   }
 
@@ -1110,7 +1110,7 @@ class CountingUserTblPropCollectorFactory
       uint32_t expected_column_family_id)
       : expected_column_family_id_(expected_column_family_id),
         num_created_(0) {}
-  virtual TablePropertiesCollector* CreateTablePropertiesCollector(
+  TablePropertiesCollector* CreateTablePropertiesCollector(
       TablePropertiesCollectorFactory::Context context) override {
     EXPECT_EQ(expected_column_family_id_, context.column_family_id);
     num_created_++;
@@ -1158,7 +1158,7 @@ class CountingDeleteTabPropCollector : public TablePropertiesCollector {
 class CountingDeleteTabPropCollectorFactory
     : public TablePropertiesCollectorFactory {
  public:
-  virtual TablePropertiesCollector* CreateTablePropertiesCollector(
+  TablePropertiesCollector* CreateTablePropertiesCollector(
       TablePropertiesCollectorFactory::Context /*context*/) override {
     return new CountingDeleteTabPropCollector();
   }

db/db_range_del_test.cc

@@ -1111,14 +1111,14 @@ class MockMergeOperator : public MergeOperator {
   // Mock non-associative operator. Non-associativity is expressed by lack of
   // implementation for any `PartialMerge*` functions.
  public:
-  virtual bool FullMergeV2(const MergeOperationInput& merge_in,
+  bool FullMergeV2(const MergeOperationInput& merge_in,
-                           MergeOperationOutput* merge_out) const override {
+                   MergeOperationOutput* merge_out) const override {
     assert(merge_out != nullptr);
     merge_out->new_value = merge_in.operand_list.back().ToString();
     return true;
   }
 
-  virtual const char* Name() const override { return "MockMergeOperator"; }
+  const char* Name() const override { return "MockMergeOperator"; }
 };
 
 TEST_F(DBRangeDelTest, KeyAtOverlappingEndpointReappears) {

db/db_sst_test.cc

@@ -25,9 +25,9 @@ class DBSSTTest : public DBTestBase {
 class FlushedFileCollector : public EventListener {
  public:
   FlushedFileCollector() {}
-  ~FlushedFileCollector() {}
+  ~FlushedFileCollector() override {}
 
-  virtual void OnFlushCompleted(DB* /*db*/, const FlushJobInfo& info) override {
+  void OnFlushCompleted(DB* /*db*/, const FlushJobInfo& info) override {
     std::lock_guard<std::mutex> lock(mutex_);
     flushed_files_.push_back(info.file_path);
   }

db/db_test.cc

@@ -940,13 +940,13 @@ TEST_F(DBTest, FlushSchedule) {
 namespace {
 class KeepFilter : public CompactionFilter {
  public:
-  virtual bool Filter(int /*level*/, const Slice& /*key*/,
+  bool Filter(int /*level*/, const Slice& /*key*/, const Slice& /*value*/,
-                      const Slice& /*value*/, std::string* /*new_value*/,
+              std::string* /*new_value*/,
-                      bool* /*value_changed*/) const override {
+              bool* /*value_changed*/) const override {
     return false;
   }
 
-  virtual const char* Name() const override { return "KeepFilter"; }
+  const char* Name() const override { return "KeepFilter"; }
 };
 
 class KeepFilterFactory : public CompactionFilterFactory {
@@ -954,7 +954,7 @@ class KeepFilterFactory : public CompactionFilterFactory {
   explicit KeepFilterFactory(bool check_context = false)
       : check_context_(check_context) {}
 
-  virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
+  std::unique_ptr<CompactionFilter> CreateCompactionFilter(
       const CompactionFilter::Context& context) override {
     if (check_context_) {
       EXPECT_EQ(expect_full_compaction_.load(), context.is_full_compaction);
@@ -963,7 +963,7 @@ class KeepFilterFactory : public CompactionFilterFactory {
     return std::unique_ptr<CompactionFilter>(new KeepFilter());
   }
 
-  virtual const char* Name() const override { return "KeepFilterFactory"; }
+  const char* Name() const override { return "KeepFilterFactory"; }
   bool check_context_;
   std::atomic_bool expect_full_compaction_;
   std::atomic_bool expect_manual_compaction_;
@@ -972,14 +972,14 @@ class KeepFilterFactory : public CompactionFilterFactory {
 class DelayFilter : public CompactionFilter {
  public:
   explicit DelayFilter(DBTestBase* d) : db_test(d) {}
-  virtual bool Filter(int /*level*/, const Slice& /*key*/,
+  bool Filter(int /*level*/, const Slice& /*key*/, const Slice& /*value*/,
-                      const Slice& /*value*/, std::string* /*new_value*/,
+              std::string* /*new_value*/,
-                      bool* /*value_changed*/) const override {
+              bool* /*value_changed*/) const override {
     db_test->env_->addon_time_.fetch_add(1000);
     return true;
   }
 
-  virtual const char* Name() const override { return "DelayFilter"; }
+  const char* Name() const override { return "DelayFilter"; }
 
  private:
   DBTestBase* db_test;
@@ -988,12 +988,12 @@ class DelayFilter : public CompactionFilter {
 class DelayFilterFactory : public CompactionFilterFactory {
  public:
   explicit DelayFilterFactory(DBTestBase* d) : db_test(d) {}
-  virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
+  std::unique_ptr<CompactionFilter> CreateCompactionFilter(
       const CompactionFilter::Context& /*context*/) override {
     return std::unique_ptr<CompactionFilter>(new DelayFilter(db_test));
   }
 
-  virtual const char* Name() const override { return "DelayFilterFactory"; }
+  const char* Name() const override { return "DelayFilterFactory"; }
 
  private:
   DBTestBase* db_test;
@@ -1775,17 +1775,14 @@ TEST_F(DBTest, OverlapInLevel0) {
 TEST_F(DBTest, ComparatorCheck) {
   class NewComparator : public Comparator {
    public:
-    virtual const char* Name() const override {
+    const char* Name() const override { return "rocksdb.NewComparator"; }
-      return "rocksdb.NewComparator";
+    int Compare(const Slice& a, const Slice& b) const override {
-    }
-    virtual int Compare(const Slice& a, const Slice& b) const override {
       return BytewiseComparator()->Compare(a, b);
     }
-    virtual void FindShortestSeparator(std::string* s,
+    void FindShortestSeparator(std::string* s, const Slice& l) const override {
-                                       const Slice& l) const override {
       BytewiseComparator()->FindShortestSeparator(s, l);
     }
-    virtual void FindShortSuccessor(std::string* key) const override {
+    void FindShortSuccessor(std::string* key) const override {
       BytewiseComparator()->FindShortSuccessor(key);
     }
   };
@@ -1808,18 +1805,15 @@ TEST_F(DBTest, ComparatorCheck) {
 TEST_F(DBTest, CustomComparator) {
   class NumberComparator : public Comparator {
    public:
-    virtual const char* Name() const override {
+    const char* Name() const override { return "test.NumberComparator"; }
-      return "test.NumberComparator";
+    int Compare(const Slice& a, const Slice& b) const override {
-    }
-    virtual int Compare(const Slice& a, const Slice& b) const override {
       return ToNumber(a) - ToNumber(b);
     }
-    virtual void FindShortestSeparator(std::string* s,
+    void FindShortestSeparator(std::string* s, const Slice& l) const override {
-                                       const Slice& l) const override {
       ToNumber(*s);  // Check format
       ToNumber(l);   // Check format
     }
-    virtual void FindShortSuccessor(std::string* key) const override {
+    void FindShortSuccessor(std::string* key) const override {
       ToNumber(*key);  // Check format
     }
 
@@ -2253,7 +2247,7 @@ static void MTThreadBody(void* arg) {
 class MultiThreadedDBTest : public DBTest,
                             public ::testing::WithParamInterface<int> {
  public:
-  virtual void SetUp() override { option_config_ = GetParam(); }
+  void SetUp() override { option_config_ = GetParam(); }
 
   static std::vector<int> GenerateOptionConfigs() {
     std::vector<int> optionConfigs;
@@ -2398,7 +2392,7 @@ class ModelDB : public DB {
    public:
     KVMap map_;
 
-    virtual SequenceNumber GetSequenceNumber() const override {
+    SequenceNumber GetSequenceNumber() const override {
       // no need to call this
       assert(false);
       return 0;
@@ -2407,43 +2401,43 @@ class ModelDB : public DB {
 
   explicit ModelDB(const Options& options) : options_(options) {}
   using DB::Put;
-  virtual Status Put(const WriteOptions& o, ColumnFamilyHandle* cf,
+  Status Put(const WriteOptions& o, ColumnFamilyHandle* cf, const Slice& k,
-                     const Slice& k, const Slice& v) override {
+             const Slice& v) override {
     WriteBatch batch;
     batch.Put(cf, k, v);
     return Write(o, &batch);
   }
   using DB::Close;
-  virtual Status Close() override { return Status::OK(); }
+  Status Close() override { return Status::OK(); }
   using DB::Delete;
-  virtual Status Delete(const WriteOptions& o, ColumnFamilyHandle* cf,
+  Status Delete(const WriteOptions& o, ColumnFamilyHandle* cf,
-                        const Slice& key) override {
+                const Slice& key) override {
     WriteBatch batch;
     batch.Delete(cf, key);
     return Write(o, &batch);
   }
   using DB::SingleDelete;
-  virtual Status SingleDelete(const WriteOptions& o, ColumnFamilyHandle* cf,
+  Status SingleDelete(const WriteOptions& o, ColumnFamilyHandle* cf,
-                              const Slice& key) override {
+                      const Slice& key) override {
     WriteBatch batch;
     batch.SingleDelete(cf, key);
     return Write(o, &batch);
   }
   using DB::Merge;
-  virtual Status Merge(const WriteOptions& o, ColumnFamilyHandle* cf,
+  Status Merge(const WriteOptions& o, ColumnFamilyHandle* cf, const Slice& k,
-                       const Slice& k, const Slice& v) override {
+               const Slice& v) override {
     WriteBatch batch;
     batch.Merge(cf, k, v);
     return Write(o, &batch);
   }
   using DB::Get;
-  virtual Status Get(const ReadOptions& /*options*/, ColumnFamilyHandle* /*cf*/,
+  Status Get(const ReadOptions& /*options*/, ColumnFamilyHandle* /*cf*/,
-                     const Slice& key, PinnableSlice* /*value*/) override {
+             const Slice& key, PinnableSlice* /*value*/) override {
     return Status::NotSupported(key);
   }
 
   using DB::MultiGet;
-  virtual std::vector<Status> MultiGet(
+  std::vector<Status> MultiGet(
       const ReadOptions& /*options*/,
       const std::vector<ColumnFamilyHandle*>& /*column_family*/,
       const std::vector<Slice>& keys,
@@ -2455,7 +2449,7 @@ class ModelDB : public DB {
 
 #ifndef ROCKSDB_LITE
   using DB::IngestExternalFile;
-  virtual Status IngestExternalFile(
+  Status IngestExternalFile(
       ColumnFamilyHandle* /*column_family*/,
       const std::vector<std::string>& /*external_files*/,
       const IngestExternalFileOptions& /*options*/) override {
@@ -2463,23 +2457,23 @@ class ModelDB : public DB {
   }
 
   using DB::IngestExternalFiles;
-  virtual Status IngestExternalFiles(
+  Status IngestExternalFiles(
       const std::vector<IngestExternalFileArg>& /*args*/) override {
     return Status::NotSupported("Not implemented");
   }
 
-  virtual Status VerifyChecksum() override {
+  Status VerifyChecksum() override {
     return Status::NotSupported("Not implemented.");
   }
 
   using DB::GetPropertiesOfAllTables;
-  virtual Status GetPropertiesOfAllTables(
+  Status GetPropertiesOfAllTables(
       ColumnFamilyHandle* /*column_family*/,
       TablePropertiesCollection* /*props*/) override {
     return Status();
   }
 
-  virtual Status GetPropertiesOfTablesInRange(
+  Status GetPropertiesOfTablesInRange(
       ColumnFamilyHandle* /*column_family*/, const Range* /*range*/,
       std::size_t /*n*/, TablePropertiesCollection* /*props*/) override {
     return Status();
@@ -2487,19 +2481,18 @@ class ModelDB : public DB {
 #endif  // ROCKSDB_LITE
 
   using DB::KeyMayExist;
-  virtual bool KeyMayExist(const ReadOptions& /*options*/,
+  bool KeyMayExist(const ReadOptions& /*options*/,
-                           ColumnFamilyHandle* /*column_family*/,
+                   ColumnFamilyHandle* /*column_family*/, const Slice& /*key*/,
-                           const Slice& /*key*/, std::string* /*value*/,
+                   std::string* /*value*/,
-                           bool* value_found = nullptr) override {
+                   bool* value_found = nullptr) override {
     if (value_found != nullptr) {
       *value_found = false;
     }
     return true;  // Not Supported directly
   }
   using DB::NewIterator;
-  virtual Iterator* NewIterator(
+  Iterator* NewIterator(const ReadOptions& options,
-      const ReadOptions& options,
+                        ColumnFamilyHandle* /*column_family*/) override {
-      ColumnFamilyHandle* /*column_family*/) override {
     if (options.snapshot == nullptr) {
       KVMap* saved = new KVMap;
       *saved = map_;
@@ -2510,38 +2503,33 @@ class ModelDB : public DB {
       return new ModelIter(snapshot_state, false);
     }
   }
-  virtual Status NewIterators(
+  Status NewIterators(const ReadOptions& /*options*/,
-      const ReadOptions& /*options*/,
+                      const std::vector<ColumnFamilyHandle*>& /*column_family*/,
-      const std::vector<ColumnFamilyHandle*>& /*column_family*/,
+                      std::vector<Iterator*>* /*iterators*/) override {
-      std::vector<Iterator*>* /*iterators*/) override {
     return Status::NotSupported("Not supported yet");
   }
-  virtual const Snapshot* GetSnapshot() override {
+  const Snapshot* GetSnapshot() override {
     ModelSnapshot* snapshot = new ModelSnapshot;
     snapshot->map_ = map_;
     return snapshot;
   }
 
-  virtual void ReleaseSnapshot(const Snapshot* snapshot) override {
+  void ReleaseSnapshot(const Snapshot* snapshot) override {
     delete reinterpret_cast<const ModelSnapshot*>(snapshot);
   }
 
-  virtual Status Write(const WriteOptions& /*options*/,
+  Status Write(const WriteOptions& /*options*/, WriteBatch* batch) override {
-                       WriteBatch* batch) override {
     class Handler : public WriteBatch::Handler {
      public:
       KVMap* map_;
-      virtual void Put(const Slice& key, const Slice& value) override {
+      void Put(const Slice& key, const Slice& value) override {
         (*map_)[key.ToString()] = value.ToString();
       }
-      virtual void Merge(const Slice& /*key*/,
+      void Merge(const Slice& /*key*/, const Slice& /*value*/) override {
-                         const Slice& /*value*/) override {
         // ignore merge for now
         // (*map_)[key.ToString()] = value.ToString();
       }
-      virtual void Delete(const Slice& key) override {
+      void Delete(const Slice& key) override { map_->erase(key.ToString()); }
-        map_->erase(key.ToString());
-      }
     };
     Handler handler;
     handler.map_ = &map_;
@@ -2549,61 +2537,58 @@ class ModelDB : public DB {
   }
 
   using DB::GetProperty;
-  virtual bool GetProperty(ColumnFamilyHandle* /*column_family*/,
+  bool GetProperty(ColumnFamilyHandle* /*column_family*/,
-                           const Slice& /*property*/,
+                   const Slice& /*property*/, std::string* /*value*/) override {
-                           std::string* /*value*/) override {
     return false;
   }
   using DB::GetIntProperty;
-  virtual bool GetIntProperty(ColumnFamilyHandle* /*column_family*/,
+  bool GetIntProperty(ColumnFamilyHandle* /*column_family*/,
-                              const Slice& /*property*/,
+                      const Slice& /*property*/, uint64_t* /*value*/) override {
-                              uint64_t* /*value*/) override {
     return false;
   }
   using DB::GetMapProperty;
-  virtual bool GetMapProperty(
+  bool GetMapProperty(ColumnFamilyHandle* /*column_family*/,
-      ColumnFamilyHandle* /*column_family*/, const Slice& /*property*/,
+                      const Slice& /*property*/,
-      std::map<std::string, std::string>* /*value*/) override {
+                      std::map<std::string, std::string>* /*value*/) override {
     return false;
   }
   using DB::GetAggregatedIntProperty;
-  virtual bool GetAggregatedIntProperty(const Slice& /*property*/,
+  bool GetAggregatedIntProperty(const Slice& /*property*/,
-                                        uint64_t* /*value*/) override {
+                                uint64_t* /*value*/) override {
     return false;
   }
   using DB::GetApproximateSizes;
-  virtual void GetApproximateSizes(ColumnFamilyHandle* /*column_family*/,
+  void GetApproximateSizes(ColumnFamilyHandle* /*column_family*/,
-                                   const Range* /*range*/, int n,
+                           const Range* /*range*/, int n, uint64_t* sizes,
-                                   uint64_t* sizes,
+                           uint8_t /*include_flags*/
-                                   uint8_t /*include_flags*/
+                           = INCLUDE_FILES) override {
-                                   = INCLUDE_FILES) override {
     for (int i = 0; i < n; i++) {
       sizes[i] = 0;
     }
   }
   using DB::GetApproximateMemTableStats;
-  virtual void GetApproximateMemTableStats(
+  void GetApproximateMemTableStats(ColumnFamilyHandle* /*column_family*/,
-      ColumnFamilyHandle* /*column_family*/, const Range& /*range*/,
+                                   const Range& /*range*/,
-      uint64_t* const count, uint64_t* const size) override {
+                                   uint64_t* const count,
+                                   uint64_t* const size) override {
     *count = 0;
     *size = 0;
   }
   using DB::CompactRange;
-  virtual Status CompactRange(const CompactRangeOptions& /*options*/,
+  Status CompactRange(const CompactRangeOptions& /*options*/,
-                              ColumnFamilyHandle* /*column_family*/,
+                      ColumnFamilyHandle* /*column_family*/,
-                              const Slice* /*start*/,
+                      const Slice* /*start*/, const Slice* /*end*/) override {
-                              const Slice* /*end*/) override {
     return Status::NotSupported("Not supported operation.");
   }
 
-  virtual Status SetDBOptions(
+  Status SetDBOptions(
       const std::unordered_map<std::string, std::string>& /*new_options*/)
       override {
     return Status::NotSupported("Not supported operation.");
   }
 
   using DB::CompactFiles;
-  virtual Status CompactFiles(
+  Status CompactFiles(
       const CompactionOptions& /*compact_options*/,
       ColumnFamilyHandle* /*column_family*/,
       const std::vector<std::string>& /*input_file_names*/,
@@ -2628,69 +2613,60 @@ class ModelDB : public DB {
   }
 
   using DB::NumberLevels;
-  virtual int NumberLevels(ColumnFamilyHandle* /*column_family*/) override {
+  int NumberLevels(ColumnFamilyHandle* /*column_family*/) override { return 1; }
-    return 1;
-  }
 
   using DB::MaxMemCompactionLevel;
-  virtual int MaxMemCompactionLevel(
+  int MaxMemCompactionLevel(ColumnFamilyHandle* /*column_family*/) override {
-      ColumnFamilyHandle* /*column_family*/) override {
     return 1;
   }
 
   using DB::Level0StopWriteTrigger;
-  virtual int Level0StopWriteTrigger(
+  int Level0StopWriteTrigger(ColumnFamilyHandle* /*column_family*/) override {
-      ColumnFamilyHandle* /*column_family*/) override {
     return -1;
   }
 
-  virtual const std::string& GetName() const override { return name_; }
+  const std::string& GetName() const override { return name_; }
 
-  virtual Env* GetEnv() const override { return nullptr; }
+  Env* GetEnv() const override { return nullptr; }
 
   using DB::GetOptions;
-  virtual Options GetOptions(
+  Options GetOptions(ColumnFamilyHandle* /*column_family*/) const override {
-      ColumnFamilyHandle* /*column_family*/) const override {
     return options_;
   }
 
   using DB::GetDBOptions;
-  virtual DBOptions GetDBOptions() const override { return options_; }
+  DBOptions GetDBOptions() const override { return options_; }
 
   using DB::Flush;
-  virtual Status Flush(const rocksdb::FlushOptions& /*options*/,
+  Status Flush(const rocksdb::FlushOptions& /*options*/,
-                       ColumnFamilyHandle* /*column_family*/) override {
+               ColumnFamilyHandle* /*column_family*/) override {
     Status ret;
     return ret;
   }
-  virtual Status Flush(
+  Status Flush(
       const rocksdb::FlushOptions& /*options*/,
       const std::vector<ColumnFamilyHandle*>& /*column_families*/) override {
     return Status::OK();
   }
 
-  virtual Status SyncWAL() override { return Status::OK(); }
+  Status SyncWAL() override { return Status::OK(); }
 
 #ifndef ROCKSDB_LITE
-  virtual Status DisableFileDeletions() override { return Status::OK(); }
+  Status DisableFileDeletions() override { return Status::OK(); }
 
-  virtual Status EnableFileDeletions(bool /*force*/) override {
+  Status EnableFileDeletions(bool /*force*/) override { return Status::OK(); }
-    return Status::OK();
+  Status GetLiveFiles(std::vector<std::string>&, uint64_t* /*size*/,
-  }
+                      bool /*flush_memtable*/ = true) override {
-  virtual Status GetLiveFiles(std::vector<std::string>&, uint64_t* /*size*/,
-                              bool /*flush_memtable*/ = true) override {
     return Status::OK();
   }
 
-  virtual Status GetSortedWalFiles(VectorLogPtr& /*files*/) override {
+  Status GetSortedWalFiles(VectorLogPtr& /*files*/) override {
     return Status::OK();
   }
 
-  virtual Status DeleteFile(std::string /*name*/) override {
+  Status DeleteFile(std::string /*name*/) override { return Status::OK(); }
-    return Status::OK();
-  }
 
-  virtual Status GetUpdatesSince(
+  Status GetUpdatesSince(
       rocksdb::SequenceNumber,
       std::unique_ptr<rocksdb::TransactionLogIterator>*,
       const TransactionLogIterator::ReadOptions& /*read_options*/ =
@@ -2698,52 +2674,48 @@ class ModelDB : public DB {
     return Status::NotSupported("Not supported in Model DB");
   }
 
-  virtual void GetColumnFamilyMetaData(
+  void GetColumnFamilyMetaData(ColumnFamilyHandle* /*column_family*/,
-      ColumnFamilyHandle* /*column_family*/,
+                               ColumnFamilyMetaData* /*metadata*/) override {}
-      ColumnFamilyMetaData* /*metadata*/) override {}
 #endif  // ROCKSDB_LITE
 
-  virtual Status GetDbIdentity(std::string& /*identity*/) const override {
+  Status GetDbIdentity(std::string& /*identity*/) const override {
     return Status::OK();
   }
 
-  virtual SequenceNumber GetLatestSequenceNumber() const override { return 0; }
+  SequenceNumber GetLatestSequenceNumber() const override { return 0; }
 
-  virtual bool SetPreserveDeletesSequenceNumber(
+  bool SetPreserveDeletesSequenceNumber(SequenceNumber /*seqnum*/) override {
-      SequenceNumber /*seqnum*/) override {
     return true;
   }
 
-  virtual ColumnFamilyHandle* DefaultColumnFamily() const override {
+  ColumnFamilyHandle* DefaultColumnFamily() const override { return nullptr; }
-    return nullptr;
-  }
 
  private:
   class ModelIter : public Iterator {
    public:
     ModelIter(const KVMap* map, bool owned)
         : map_(map), owned_(owned), iter_(map_->end()) {}
-    ~ModelIter() {
+    ~ModelIter() override {
       if (owned_) delete map_;
     }
-    virtual bool Valid() const override { return iter_ != map_->end(); }
+    bool Valid() const override { return iter_ != map_->end(); }
-    virtual void SeekToFirst() override { iter_ = map_->begin(); }
+    void SeekToFirst() override { iter_ = map_->begin(); }
-    virtual void SeekToLast() override {
+    void SeekToLast() override {
       if (map_->empty()) {
         iter_ = map_->end();
       } else {
         iter_ = map_->find(map_->rbegin()->first);
       }
     }
-    virtual void Seek(const Slice& k) override {
+    void Seek(const Slice& k) override {
       iter_ = map_->lower_bound(k.ToString());
     }
-    virtual void SeekForPrev(const Slice& k) override {
+    void SeekForPrev(const Slice& k) override {
       iter_ = map_->upper_bound(k.ToString());
       Prev();
     }
-    virtual void Next() override { ++iter_; }
+    void Next() override { ++iter_; }
-    virtual void Prev() override {
+    void Prev() override {
       if (iter_ == map_->begin()) {
         iter_ = map_->end();
         return;
@@ -2751,9 +2723,9 @@ class ModelDB : public DB {
       --iter_;
     }
 
-    virtual Slice key() const override { return iter_->first; }
+    Slice key() const override { return iter_->first; }
-    virtual Slice value() const override { return iter_->second; }
+    Slice value() const override { return iter_->second; }
-    virtual Status status() const override { return Status::OK(); }
+    Status status() const override { return Status::OK(); }
 
    private:
     const KVMap* const map_;
@@ -2821,7 +2793,7 @@ static bool CompareIterators(int step, DB* model, DB* db,
 class DBTestRandomized : public DBTest,
                          public ::testing::WithParamInterface<int> {
  public:
-  virtual void SetUp() override { option_config_ = GetParam(); }
+  void SetUp() override { option_config_ = GetParam(); }
 
   static std::vector<int> GenerateOptionConfigs() {
     std::vector<int> option_configs;
@@ -5043,14 +5015,14 @@ class DelayedMergeOperator : public MergeOperator {
  public:
   explicit DelayedMergeOperator(DBTest* d) : db_test_(d) {}
 
-  virtual bool FullMergeV2(const MergeOperationInput& /*merge_in*/,
+  bool FullMergeV2(const MergeOperationInput& /*merge_in*/,
-                           MergeOperationOutput* merge_out) const override {
+                   MergeOperationOutput* merge_out) const override {
     db_test_->env_->addon_time_.fetch_add(1000);
     merge_out->new_value = "";
     return true;
   }
 
-  virtual const char* Name() const override { return "DelayedMergeOperator"; }
+  const char* Name() const override { return "DelayedMergeOperator"; }
 };
 
 TEST_F(DBTest, MergeTestTime) {
@@ -5186,7 +5158,7 @@ TEST_F(DBTest, EmptyCompactedDB) {
 TEST_F(DBTest, SuggestCompactRangeTest) {
   class CompactionFilterFactoryGetContext : public CompactionFilterFactory {
    public:
-    virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
+    std::unique_ptr<CompactionFilter> CreateCompactionFilter(
         const CompactionFilter::Context& context) override {
       saved_context = context;
       std::unique_ptr<CompactionFilter> empty_filter;

db/db_test2.cc

@@ -30,7 +30,7 @@ class PrefixFullBloomWithReverseComparator
  public:
   PrefixFullBloomWithReverseComparator()
       : DBTestBase("/prefix_bloom_reverse") {}
-  virtual void SetUp() override { if_cache_filter_ = GetParam(); }
+  void SetUp() override { if_cache_filter_ = GetParam(); }
   bool if_cache_filter_;
 };
 
@@ -515,9 +515,9 @@ TEST_F(DBTest2, WalFilterTest) {
       apply_option_at_record_index_(apply_option_for_record_index),
       current_record_index_(0) {}
 
-    virtual WalProcessingOption LogRecord(
+    WalProcessingOption LogRecord(const WriteBatch& /*batch*/,
-        const WriteBatch& /*batch*/, WriteBatch* /*new_batch*/,
+                                  WriteBatch* /*new_batch*/,
-        bool* /*batch_changed*/) const override {
+                                  bool* /*batch_changed*/) const override {
       WalFilter::WalProcessingOption option_to_return;
 
       if (current_record_index_ == apply_option_at_record_index_) {
@@ -535,7 +535,7 @@ TEST_F(DBTest2, WalFilterTest) {
       return option_to_return;
     }
 
-    virtual const char* Name() const override { return "TestWalFilter"; }
+    const char* Name() const override { return "TestWalFilter"; }
   };
 
   // Create 3 batches with two keys each
@@ -687,7 +687,7 @@ TEST_F(DBTest2, WalFilterTestWithChangeBatch) {
       : new_write_batch_(new_write_batch),
       num_keys_to_add_in_new_batch_(num_keys_to_add_in_new_batch),
       num_keys_added_(0) {}
-    virtual void Put(const Slice& key, const Slice& value) override {
+    void Put(const Slice& key, const Slice& value) override {
       if (num_keys_added_ < num_keys_to_add_in_new_batch_) {
         new_write_batch_->Put(key, value);
         ++num_keys_added_;
@@ -711,9 +711,9 @@ TEST_F(DBTest2, WalFilterTestWithChangeBatch) {
       num_keys_to_add_in_new_batch_(num_keys_to_add_in_new_batch),
       current_record_index_(0) {}
 
-    virtual WalProcessingOption LogRecord(const WriteBatch& batch,
+    WalProcessingOption LogRecord(const WriteBatch& batch,
-      WriteBatch* new_batch,
+                                  WriteBatch* new_batch,
-      bool* batch_changed) const override {
+                                  bool* batch_changed) const override {
       if (current_record_index_ >= change_records_from_index_) {
         ChangeBatchHandler handler(new_batch, num_keys_to_add_in_new_batch_);
         batch.Iterate(&handler);
@@ -729,9 +729,7 @@ TEST_F(DBTest2, WalFilterTestWithChangeBatch) {
       return WalProcessingOption::kContinueProcessing;
     }
 
-    virtual const char* Name() const override {
+    const char* Name() const override { return "TestWalFilterWithChangeBatch"; }
-      return "TestWalFilterWithChangeBatch";
-    }
   };
 
   std::vector<std::vector<std::string>> batch_keys(3);
@@ -809,18 +807,17 @@ TEST_F(DBTest2, WalFilterTestWithChangeBatch) {
 TEST_F(DBTest2, WalFilterTestWithChangeBatchExtraKeys) {
   class TestWalFilterWithChangeBatchAddExtraKeys : public WalFilter {
   public:
-    virtual WalProcessingOption LogRecord(const WriteBatch& batch,
+   WalProcessingOption LogRecord(const WriteBatch& batch, WriteBatch* new_batch,
-      WriteBatch* new_batch,
+                                 bool* batch_changed) const override {
-      bool* batch_changed) const override {
+     *new_batch = batch;
-      *new_batch = batch;
+     new_batch->Put("key_extra", "value_extra");
-      new_batch->Put("key_extra", "value_extra");
+     *batch_changed = true;
-      *batch_changed = true;
+     return WalProcessingOption::kContinueProcessing;
-      return WalProcessingOption::kContinueProcessing;
+   }
-    }
+
-
+   const char* Name() const override {
-    virtual const char* Name() const override {
+     return "WalFilterTestWithChangeBatchExtraKeys";
-      return "WalFilterTestWithChangeBatchExtraKeys";
+   }
-    }
   };
 
   std::vector<std::vector<std::string>> batch_keys(3);
@@ -884,18 +881,19 @@ TEST_F(DBTest2, WalFilterTestWithColumnFamilies) {
     // for verification against the keys we expect.
     std::map<uint32_t, std::vector<std::string>> cf_wal_keys_;
   public:
-    virtual void ColumnFamilyLogNumberMap(
+   void ColumnFamilyLogNumberMap(
-      const std::map<uint32_t, uint64_t>& cf_lognumber_map,
+       const std::map<uint32_t, uint64_t>& cf_lognumber_map,
-      const std::map<std::string, uint32_t>& cf_name_id_map) override {
+       const std::map<std::string, uint32_t>& cf_name_id_map) override {
-      cf_log_number_map_ = cf_lognumber_map;
+     cf_log_number_map_ = cf_lognumber_map;
-      cf_name_id_map_ = cf_name_id_map;
+     cf_name_id_map_ = cf_name_id_map;
-    }
+   }
-
+
-    virtual WalProcessingOption LogRecordFound(
+   WalProcessingOption LogRecordFound(unsigned long long log_number,
-        unsigned long long log_number, const std::string& /*log_file_name*/,
+                                      const std::string& /*log_file_name*/,
-        const WriteBatch& batch, WriteBatch* /*new_batch*/,
+                                      const WriteBatch& batch,
-        bool* /*batch_changed*/) override {
+                                      WriteBatch* /*new_batch*/,
-      class LogRecordBatchHandler : public WriteBatch::Handler {
+                                      bool* /*batch_changed*/) override {
+     class LogRecordBatchHandler : public WriteBatch::Handler {
       private:
         const std::map<uint32_t, uint64_t> & cf_log_number_map_;
         std::map<uint32_t, std::vector<std::string>> & cf_wal_keys_;
@@ -908,8 +906,8 @@ TEST_F(DBTest2, WalFilterTestWithColumnFamilies) {
           cf_wal_keys_(cf_wal_keys),
           log_number_(current_log_number){}
 
-        virtual Status PutCF(uint32_t column_family_id, const Slice& key,
+        Status PutCF(uint32_t column_family_id, const Slice& key,
-          const Slice& /*value*/) override {
+                     const Slice& /*value*/) override {
           auto it = cf_log_number_map_.find(column_family_id);
           assert(it != cf_log_number_map_.end());
           unsigned long long log_number_for_cf = it->second;
@@ -927,11 +925,11 @@ TEST_F(DBTest2, WalFilterTestWithColumnFamilies) {
       batch.Iterate(&handler);
 
       return WalProcessingOption::kContinueProcessing;
-    }
+   }
 
-    virtual const char* Name() const override {
+   const char* Name() const override {
-      return "WalFilterTestWithColumnFamilies";
+     return "WalFilterTestWithColumnFamilies";
-    }
+   }
 
     const std::map<uint32_t, std::vector<std::string>>& GetColumnFamilyKeys() {
       return cf_wal_keys_;
@@ -1452,7 +1450,7 @@ class PinL0IndexAndFilterBlocksTest
       public testing::WithParamInterface<std::tuple<bool, bool>> {
  public:
   PinL0IndexAndFilterBlocksTest() : DBTestBase("/db_pin_l0_index_bloom_test") {}
-  virtual void SetUp() override {
+  void SetUp() override {
     infinite_max_files_ = std::get<0>(GetParam());
     disallow_preload_ = std::get<1>(GetParam());
   }
@@ -1755,7 +1753,7 @@ class MockPersistentCache : public PersistentCache {
         "GetUniqueIdFromFile:FS_IOC_GETVERSION", UniqueIdCallback);
   }
 
-  virtual ~MockPersistentCache() {}
+  ~MockPersistentCache() override {}
 
   PersistentCache::StatsType Stats() override {
     return PersistentCache::StatsType();
@@ -2646,9 +2644,7 @@ TEST_F(DBTest2, ReadCallbackTest) {
   class TestReadCallback : public ReadCallback {
    public:
     explicit TestReadCallback(SequenceNumber snapshot) : snapshot_(snapshot) {}
-    virtual bool IsVisible(SequenceNumber seq) override {
+    bool IsVisible(SequenceNumber seq) override { return seq <= snapshot_; }
-      return seq <= snapshot_;
-    }
 
    private:
     SequenceNumber snapshot_;

db/db_universal_compaction_test.cc

@@ -27,7 +27,7 @@ class DBTestUniversalCompactionBase
  public:
   explicit DBTestUniversalCompactionBase(
       const std::string& path) : DBTestBase(path) {}
-  virtual void SetUp() override {
+  void SetUp() override {
     num_levels_ = std::get<0>(GetParam());
     exclusive_manual_compaction_ = std::get<1>(GetParam());
   }
@@ -63,13 +63,13 @@ void VerifyCompactionResult(
 
 class KeepFilter : public CompactionFilter {
  public:
-  virtual bool Filter(int /*level*/, const Slice& /*key*/,
+  bool Filter(int /*level*/, const Slice& /*key*/, const Slice& /*value*/,
-                      const Slice& /*value*/, std::string* /*new_value*/,
+              std::string* /*new_value*/,
-                      bool* /*value_changed*/) const override {
+              bool* /*value_changed*/) const override {
     return false;
   }
 
-  virtual const char* Name() const override { return "KeepFilter"; }
+  const char* Name() const override { return "KeepFilter"; }
 };
 
 class KeepFilterFactory : public CompactionFilterFactory {
@@ -77,7 +77,7 @@ class KeepFilterFactory : public CompactionFilterFactory {
   explicit KeepFilterFactory(bool check_context = false)
       : check_context_(check_context) {}
 
-  virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
+  std::unique_ptr<CompactionFilter> CreateCompactionFilter(
       const CompactionFilter::Context& context) override {
     if (check_context_) {
       EXPECT_EQ(expect_full_compaction_.load(), context.is_full_compaction);
@@ -86,7 +86,7 @@ class KeepFilterFactory : public CompactionFilterFactory {
     return std::unique_ptr<CompactionFilter>(new KeepFilter());
   }
 
-  virtual const char* Name() const override { return "KeepFilterFactory"; }
+  const char* Name() const override { return "KeepFilterFactory"; }
   bool check_context_;
   std::atomic_bool expect_full_compaction_;
   std::atomic_bool expect_manual_compaction_;
@@ -95,14 +95,14 @@ class KeepFilterFactory : public CompactionFilterFactory {
 class DelayFilter : public CompactionFilter {
  public:
   explicit DelayFilter(DBTestBase* d) : db_test(d) {}
-  virtual bool Filter(int /*level*/, const Slice& /*key*/,
+  bool Filter(int /*level*/, const Slice& /*key*/, const Slice& /*value*/,
-                      const Slice& /*value*/, std::string* /*new_value*/,
+              std::string* /*new_value*/,
-                      bool* /*value_changed*/) const override {
+              bool* /*value_changed*/) const override {
     db_test->env_->addon_time_.fetch_add(1000);
     return true;
   }
 
-  virtual const char* Name() const override { return "DelayFilter"; }
+  const char* Name() const override { return "DelayFilter"; }
 
  private:
   DBTestBase* db_test;
@@ -111,12 +111,12 @@ class DelayFilter : public CompactionFilter {
 class DelayFilterFactory : public CompactionFilterFactory {
  public:
   explicit DelayFilterFactory(DBTestBase* d) : db_test(d) {}
-  virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
+  std::unique_ptr<CompactionFilter> CreateCompactionFilter(
       const CompactionFilter::Context& /*context*/) override {
     return std::unique_ptr<CompactionFilter>(new DelayFilter(db_test));
   }
 
-  virtual const char* Name() const override { return "DelayFilterFactory"; }
+  const char* Name() const override { return "DelayFilterFactory"; }
 
  private:
   DBTestBase* db_test;

db/external_sst_file_basic_test.cc

@@ -134,7 +134,9 @@ class ExternalSSTFileBasicTest
         write_global_seqno, verify_checksums_before_ingest, true_data);
   }
 
-  ~ExternalSSTFileBasicTest() { test::DestroyDir(env_, sst_files_dir_); }
+  ~ExternalSSTFileBasicTest() override {
+    test::DestroyDir(env_, sst_files_dir_);
+  }
 
  protected:
   std::string sst_files_dir_;

db/external_sst_file_test.cc

@@ -283,7 +283,7 @@ class ExternalSSTFileTest
     return db_->IngestExternalFile(files, opts);
   }
 
-  ~ExternalSSTFileTest() { test::DestroyDir(env_, sst_files_dir_); }
+  ~ExternalSSTFileTest() override { test::DestroyDir(env_, sst_files_dir_); }
 
  protected:
   int last_file_id_ = 0;
@@ -571,7 +571,7 @@ class SstFileWriterCollector : public TablePropertiesCollector {
     return Status::OK();
   }
 
-  virtual UserCollectedProperties GetReadableProperties() const override {
+  UserCollectedProperties GetReadableProperties() const override {
     return UserCollectedProperties{};
   }
 
@@ -585,7 +585,7 @@ class SstFileWriterCollectorFactory : public TablePropertiesCollectorFactory {
  public:
   explicit SstFileWriterCollectorFactory(std::string prefix)
       : prefix_(prefix), num_created_(0) {}
-  virtual TablePropertiesCollector* CreateTablePropertiesCollector(
+  TablePropertiesCollector* CreateTablePropertiesCollector(
       TablePropertiesCollectorFactory::Context /*context*/) override {
     num_created_++;
     return new SstFileWriterCollector(prefix_);

db/fault_injection_test.cc

@@ -83,7 +83,7 @@ class FaultInjectionTest
         env_(nullptr),
         db_(nullptr) {}
 
-  ~FaultInjectionTest() {
+  ~FaultInjectionTest() override {
     rocksdb::SyncPoint::GetInstance()->DisableProcessing();
     rocksdb::SyncPoint::GetInstance()->ClearAllCallBacks();
   }

db/file_indexer_test.cc

@@ -47,7 +47,7 @@ class FileIndexerTest : public testing::Test {
   FileIndexerTest()
       : kNumLevels(4), files(new std::vector<FileMetaData*>[kNumLevels]) {}
 
-  ~FileIndexerTest() {
+  ~FileIndexerTest() override {
     ClearFiles();
     delete[] files;
   }

db/forward_iterator.cc

@@ -46,7 +46,7 @@ class ForwardLevelIterator : public InternalIterator {
         pinned_iters_mgr_(nullptr),
         prefix_extractor_(prefix_extractor) {}
 
-  ~ForwardLevelIterator() {
+  ~ForwardLevelIterator() override {
     // Reset current pointer
     if (pinned_iters_mgr_ && pinned_iters_mgr_->PinningEnabled()) {
       pinned_iters_mgr_->PinIterator(file_iter_);

db/listener_test.cc

@@ -46,22 +46,20 @@ class EventListenerTest : public DBTestBase {
 };
 
 struct TestPropertiesCollector : public rocksdb::TablePropertiesCollector {
-  virtual rocksdb::Status AddUserKey(const rocksdb::Slice& /*key*/,
+  rocksdb::Status AddUserKey(const rocksdb::Slice& /*key*/,
-                                     const rocksdb::Slice& /*value*/,
+                             const rocksdb::Slice& /*value*/,
-                                     rocksdb::EntryType /*type*/,
+                             rocksdb::EntryType /*type*/,
-                                     rocksdb::SequenceNumber /*seq*/,
+                             rocksdb::SequenceNumber /*seq*/,
-                                     uint64_t /*file_size*/) override {
+                             uint64_t /*file_size*/) override {
     return Status::OK();
   }
-  virtual rocksdb::Status Finish(
+  rocksdb::Status Finish(
       rocksdb::UserCollectedProperties* properties) override {
     properties->insert({"0", "1"});
     return Status::OK();
   }
 
-  virtual const char* Name() const override {
+  const char* Name() const override { return "TestTablePropertiesCollector"; }
-    return "TestTablePropertiesCollector";
-  }
 
   rocksdb::UserCollectedProperties GetReadableProperties() const override {
     rocksdb::UserCollectedProperties ret;
@@ -72,7 +70,7 @@ struct TestPropertiesCollector : public rocksdb::TablePropertiesCollector {
 
 class TestPropertiesCollectorFactory : public TablePropertiesCollectorFactory {
  public:
-  virtual TablePropertiesCollector* CreateTablePropertiesCollector(
+  TablePropertiesCollector* CreateTablePropertiesCollector(
       TablePropertiesCollectorFactory::Context /*context*/) override {
     return new TestPropertiesCollector;
   }
@@ -603,7 +601,7 @@ class TableFileCreationListener : public EventListener {
 
     Status NewWritableFile(const std::string& fname,
                            std::unique_ptr<WritableFile>* result,
-                           const EnvOptions& options) {
+                           const EnvOptions& options) override {
       if (fname.size() > 4 && fname.substr(fname.size() - 4) == ".sst") {
         if (!status_.ok()) {
           return status_;

db/log_test.cc

@@ -61,7 +61,7 @@ class LogTest : public ::testing::TestWithParam<int> {
       force_eof_position_(0),
       returned_partial_(false) { }
 
-    virtual Status Read(size_t n, Slice* result, char* scratch) override {
+    Status Read(size_t n, Slice* result, char* scratch) override {
       EXPECT_TRUE(!returned_partial_) << "must not Read() after eof/error";
 
       if (force_error_) {
@@ -100,7 +100,7 @@ class LogTest : public ::testing::TestWithParam<int> {
       return Status::OK();
     }
 
-    virtual Status Skip(uint64_t n) override {
+    Status Skip(uint64_t n) override {
       if (n > contents_.size()) {
         contents_.clear();
         return Status::NotFound("in-memory file skipepd past end");
@@ -118,7 +118,7 @@ class LogTest : public ::testing::TestWithParam<int> {
     std::string message_;
 
     ReportCollector() : dropped_bytes_(0) { }
-    virtual void Corruption(size_t bytes, const Status& status) override {
+    void Corruption(size_t bytes, const Status& status) override {
       dropped_bytes_ += bytes;
       message_.append(status.ToString());
     }
@@ -661,7 +661,7 @@ class RetriableLogTest : public ::testing::TestWithParam<int> {
     std::string message_;
 
     ReportCollector() : dropped_bytes_(0) {}
-    virtual void Corruption(size_t bytes, const Status& status) override {
+    void Corruption(size_t bytes, const Status& status) override {
       dropped_bytes_ += bytes;
       message_.append(status.ToString());
     }

db/manual_compaction_test.cc

@@ -51,15 +51,13 @@ class DestroyAllCompactionFilter : public CompactionFilter {
  public:
   DestroyAllCompactionFilter() {}
 
-  virtual bool Filter(int /*level*/, const Slice& /*key*/,
+  bool Filter(int /*level*/, const Slice& /*key*/, const Slice& existing_value,
-                      const Slice& existing_value, std::string* /*new_value*/,
+              std::string* /*new_value*/,
-                      bool* /*value_changed*/) const override {
+              bool* /*value_changed*/) const override {
     return existing_value.ToString() == "destroy";
   }
 
-  virtual const char* Name() const override {
+  const char* Name() const override { return "DestroyAllCompactionFilter"; }
-    return "DestroyAllCompactionFilter";
-  }
 };
 
 TEST_F(ManualCompactionTest, CompactTouchesAllKeys) {

db/memtable.cc

@@ -289,7 +289,7 @@ class MemTableIterator : public InternalIterator {
     }
   }
 
-  ~MemTableIterator() {
+  ~MemTableIterator() override {
 #ifndef NDEBUG
     // Assert that the MemTableIterator is never deleted while
     // Pinning is Enabled.
@@ -303,15 +303,14 @@ class MemTableIterator : public InternalIterator {
   }
 
 #ifndef NDEBUG
-  virtual void SetPinnedItersMgr(
+  void SetPinnedItersMgr(PinnedIteratorsManager* pinned_iters_mgr) override {
-      PinnedIteratorsManager* pinned_iters_mgr) override {
     pinned_iters_mgr_ = pinned_iters_mgr;
   }
   PinnedIteratorsManager* pinned_iters_mgr_ = nullptr;
 #endif
 
-  virtual bool Valid() const override { return valid_; }
+  bool Valid() const override { return valid_; }
-  virtual void Seek(const Slice& k) override {
+  void Seek(const Slice& k) override {
     PERF_TIMER_GUARD(seek_on_memtable_time);
     PERF_COUNTER_ADD(seek_on_memtable_count, 1);
     if (bloom_ != nullptr) {
@@ -327,7 +326,7 @@ class MemTableIterator : public InternalIterator {
     iter_->Seek(k, nullptr);
     valid_ = iter_->Valid();
   }
-  virtual void SeekForPrev(const Slice& k) override {
+  void SeekForPrev(const Slice& k) override {
     PERF_TIMER_GUARD(seek_on_memtable_time);
     PERF_COUNTER_ADD(seek_on_memtable_count, 1);
     if (bloom_ != nullptr) {
@@ -349,44 +348,44 @@ class MemTableIterator : public InternalIterator {
       Prev();
     }
   }
-  virtual void SeekToFirst() override {
+  void SeekToFirst() override {
     iter_->SeekToFirst();
     valid_ = iter_->Valid();
   }
-  virtual void SeekToLast() override {
+  void SeekToLast() override {
     iter_->SeekToLast();
     valid_ = iter_->Valid();
   }
-  virtual void Next() override {
+  void Next() override {
     PERF_COUNTER_ADD(next_on_memtable_count, 1);
     assert(Valid());
     iter_->Next();
     valid_ = iter_->Valid();
   }
-  virtual void Prev() override {
+  void Prev() override {
     PERF_COUNTER_ADD(prev_on_memtable_count, 1);
     assert(Valid());
     iter_->Prev();
     valid_ = iter_->Valid();
   }
-  virtual Slice key() const override {
+  Slice key() const override {
     assert(Valid());
     return GetLengthPrefixedSlice(iter_->key());
   }
-  virtual Slice value() const override {
+  Slice value() const override {
     assert(Valid());
     Slice key_slice = GetLengthPrefixedSlice(iter_->key());
     return GetLengthPrefixedSlice(key_slice.data() + key_slice.size());
   }
 
-  virtual Status status() const override { return Status::OK(); }
+  Status status() const override { return Status::OK(); }
 
-  virtual bool IsKeyPinned() const override {
+  bool IsKeyPinned() const override {
     // memtable data is always pinned
     return true;
   }
 
-  virtual bool IsValuePinned() const override {
+  bool IsValuePinned() const override {
     // memtable value is always pinned, except if we allow inplace update.
     return value_pinned_;
   }

db/memtable_list_test.cc

@@ -62,7 +62,7 @@ class MemTableListTest : public testing::Test {
     }
   }
 
-  ~MemTableListTest() {
+  ~MemTableListTest() override {
     if (db) {
       std::vector<ColumnFamilyDescriptor> cf_descs(handles.size());
       for (int i = 0; i != static_cast<int>(handles.size()); ++i) {

db/merge_helper_test.cc

@@ -20,7 +20,7 @@ class MergeHelperTest : public testing::Test {
  public:
   MergeHelperTest() { env_ = Env::Default(); }
 
-  ~MergeHelperTest() = default;
+  ~MergeHelperTest() override = default;
 
   Status Run(SequenceNumber stop_before, bool at_bottom,
              SequenceNumber latest_snapshot = 0) {

db/merge_test.cc

@@ -38,11 +38,8 @@ class CountMergeOperator : public AssociativeMergeOperator {
     mergeOperator_ = MergeOperators::CreateUInt64AddOperator();
   }
 
-  virtual bool Merge(const Slice& key,
+  bool Merge(const Slice& key, const Slice* existing_value, const Slice& value,
-                     const Slice* existing_value,
+             std::string* new_value, Logger* logger) const override {
-                     const Slice& value,
-                     std::string* new_value,
-                     Logger* logger) const override {
     assert(new_value->empty());
     ++num_merge_operator_calls;
     if (existing_value == nullptr) {
@@ -58,19 +55,17 @@ class CountMergeOperator : public AssociativeMergeOperator {
         logger);
   }
 
-  virtual bool PartialMergeMulti(const Slice& key,
+  bool PartialMergeMulti(const Slice& key,
-                                 const std::deque<Slice>& operand_list,
+                         const std::deque<Slice>& operand_list,
-                                 std::string* new_value,
+                         std::string* new_value,
-                                 Logger* logger) const override {
+                         Logger* logger) const override {
     assert(new_value->empty());
     ++num_partial_merge_calls;
     return mergeOperator_->PartialMergeMulti(key, operand_list, new_value,
                                              logger);
   }
 
-  virtual const char* Name() const override {
+  const char* Name() const override { return "UInt64AddOperator"; }
-    return "UInt64AddOperator";
-  }
 
  private:
   std::shared_ptr<MergeOperator> mergeOperator_;
@@ -230,7 +225,7 @@ class MergeBasedCounters : public Counters {
   }
 
   // mapped to a rocksdb Merge operation
-  virtual bool add(const std::string& key, uint64_t value) override {
+  bool add(const std::string& key, uint64_t value) override {
     char encoded[sizeof(uint64_t)];
     EncodeFixed64(encoded, value);
     Slice slice(encoded, sizeof(uint64_t));

db/plain_table_db_test.cc

@@ -109,7 +109,7 @@ class PlainTableDBTest : public testing::Test,
  public:
   PlainTableDBTest() : env_(Env::Default()) {}
 
-  ~PlainTableDBTest() {
+  ~PlainTableDBTest() override {
     delete db_;
     EXPECT_OK(DestroyDB(dbname_, Options()));
   }
@@ -290,10 +290,10 @@ class TestPlainTableReader : public PlainTableReader {
     EXPECT_EQ(column_family_name, props->column_family_name);
   }
 
-  virtual ~TestPlainTableReader() {}
+  ~TestPlainTableReader() override {}
 
  private:
-  virtual bool MatchBloom(uint32_t hash) const override {
+  bool MatchBloom(uint32_t hash) const override {
     bool ret = PlainTableReader::MatchBloom(hash);
     if (*expect_bloom_not_match_) {
       EXPECT_TRUE(!ret);

db/prefix_test.cc

@@ -83,7 +83,7 @@ class TestKeyComparator : public Comparator {
 
   // Compare needs to be aware of the possibility of a and/or b is
   // prefix only
-  virtual int Compare(const Slice& a, const Slice& b) const override {
+  int Compare(const Slice& a, const Slice& b) const override {
     const TestKey kkey_a = SliceToTestKey(a);
     const TestKey kkey_b = SliceToTestKey(b);
     const TestKey *key_a = &kkey_a;
@@ -122,14 +122,12 @@ class TestKeyComparator : public Comparator {
     return Compare(TestKeyToSlice(sa, a), TestKeyToSlice(sb, b)) < 0;
   }
 
-  virtual const char* Name() const override {
+  const char* Name() const override { return "TestKeyComparator"; }
-    return "TestKeyComparator";
-  }
 
-  virtual void FindShortestSeparator(std::string* /*start*/,
+  void FindShortestSeparator(std::string* /*start*/,
-                                     const Slice& /*limit*/) const override {}
+                             const Slice& /*limit*/) const override {}
 
-  virtual void FindShortSuccessor(std::string* /*key*/) const override {}
+  void FindShortSuccessor(std::string* /*key*/) const override {}
 };
 
 namespace {
@@ -195,27 +193,23 @@ class SamePrefixTransform : public SliceTransform {
   explicit SamePrefixTransform(const Slice& prefix)
       : prefix_(prefix), name_("rocksdb.SamePrefix." + prefix.ToString()) {}
 
-  virtual const char* Name() const override { return name_.c_str(); }
+  const char* Name() const override { return name_.c_str(); }
 
-  virtual Slice Transform(const Slice& src) const override {
+  Slice Transform(const Slice& src) const override {
     assert(InDomain(src));
     return prefix_;
   }
 
-  virtual bool InDomain(const Slice& src) const override {
+  bool InDomain(const Slice& src) const override {
     if (src.size() >= prefix_.size()) {
       return Slice(src.data(), prefix_.size()) == prefix_;
     }
     return false;
   }
 
-  virtual bool InRange(const Slice& dst) const override {
+  bool InRange(const Slice& dst) const override { return dst == prefix_; }
-    return dst == prefix_;
-  }
 
-  virtual bool FullLengthEnabled(size_t* /*len*/) const override {
+  bool FullLengthEnabled(size_t* /*len*/) const override { return false; }
-    return false;
-  }
 };
 
 }  // namespace
@@ -283,9 +277,8 @@ class PrefixTest : public testing::Test {
   PrefixTest() : option_config_(kBegin) {
     options.comparator = new TestKeyComparator();
   }
-  ~PrefixTest() {
+  ~PrefixTest() override { delete options.comparator; }
-    delete options.comparator;
+
-  }
  protected:
   enum OptionConfig {
     kBegin,

db/repair.cc

@@ -336,7 +336,7 @@ class Repairer {
       Env* env;
       std::shared_ptr<Logger> info_log;
       uint64_t lognum;
-      virtual void Corruption(size_t bytes, const Status& s) override {
+      void Corruption(size_t bytes, const Status& s) override {
         // We print error messages for corruption, but continue repairing.
         ROCKS_LOG_ERROR(info_log, "Log #%" PRIu64 ": dropping %d bytes; %s",
                         lognum, static_cast<int>(bytes), s.ToString().c_str());

db/table_properties_collector_test.cc

@@ -28,7 +28,7 @@ namespace rocksdb {
 class TablePropertiesTest : public testing::Test,
                             public testing::WithParamInterface<bool> {
  public:
-  virtual void SetUp() override { backward_mode_ = GetParam(); }
+  void SetUp() override { backward_mode_ = GetParam(); }
 
   bool backward_mode_;
 };
@@ -106,7 +106,7 @@ class RegularKeysStartWithA: public TablePropertiesCollector {
     return Status::OK();
   }
 
-  virtual UserCollectedProperties GetReadableProperties() const override {
+  UserCollectedProperties GetReadableProperties() const override {
     return UserCollectedProperties{};
   }
 
@@ -143,7 +143,7 @@ class RegularKeysStartWithABackwardCompatible
     return Status::OK();
   }
 
-  virtual UserCollectedProperties GetReadableProperties() const override {
+  UserCollectedProperties GetReadableProperties() const override {
     return UserCollectedProperties{};
   }
 
@@ -172,7 +172,7 @@ class RegularKeysStartWithAInternal : public IntTblPropCollector {
     return Status::OK();
   }
 
-  virtual UserCollectedProperties GetReadableProperties() const override {
+  UserCollectedProperties GetReadableProperties() const override {
     return UserCollectedProperties{};
   }
 
@@ -185,7 +185,7 @@ class RegularKeysStartWithAFactory : public IntTblPropCollectorFactory,
  public:
   explicit RegularKeysStartWithAFactory(bool backward_mode)
       : backward_mode_(backward_mode) {}
-  virtual TablePropertiesCollector* CreateTablePropertiesCollector(
+  TablePropertiesCollector* CreateTablePropertiesCollector(
       TablePropertiesCollectorFactory::Context context) override {
     EXPECT_EQ(kTestColumnFamilyId, context.column_family_id);
     if (!backward_mode_) {
@@ -194,7 +194,7 @@ class RegularKeysStartWithAFactory : public IntTblPropCollectorFactory,
       return new RegularKeysStartWithABackwardCompatible();
     }
   }
-  virtual IntTblPropCollector* CreateIntTblPropCollector(
+  IntTblPropCollector* CreateIntTblPropCollector(
       uint32_t /*column_family_id*/) override {
     return new RegularKeysStartWithAInternal();
   }
@@ -205,7 +205,7 @@ class RegularKeysStartWithAFactory : public IntTblPropCollectorFactory,
 
 class FlushBlockEveryThreePolicy : public FlushBlockPolicy {
  public:
-  virtual bool Update(const Slice& /*key*/, const Slice& /*value*/) override {
+  bool Update(const Slice& /*key*/, const Slice& /*value*/) override {
     return (++count_ % 3U == 0);
   }
 

memtable/hash_linklist_rep.cc

@@ -168,24 +168,23 @@ class HashLinkListRep : public MemTableRep {
                   int bucket_entries_logging_threshold,
                   bool if_log_bucket_dist_when_flash);
 
-  virtual KeyHandle Allocate(const size_t len, char** buf) override;
+  KeyHandle Allocate(const size_t len, char** buf) override;
 
-  virtual void Insert(KeyHandle handle) override;
+  void Insert(KeyHandle handle) override;
 
-  virtual bool Contains(const char* key) const override;
+  bool Contains(const char* key) const override;
 
-  virtual size_t ApproximateMemoryUsage() override;
+  size_t ApproximateMemoryUsage() override;
 
-  virtual void Get(const LookupKey& k, void* callback_args,
+  void Get(const LookupKey& k, void* callback_args,
-                   bool (*callback_func)(void* arg,
+           bool (*callback_func)(void* arg, const char* entry)) override;
-                                         const char* entry)) override;
 
-  virtual ~HashLinkListRep();
+  ~HashLinkListRep() override;
 
-  virtual MemTableRep::Iterator* GetIterator(Arena* arena = nullptr) override;
+  MemTableRep::Iterator* GetIterator(Arena* arena = nullptr) override;
 
-  virtual MemTableRep::Iterator* GetDynamicPrefixIterator(
+  MemTableRep::Iterator* GetDynamicPrefixIterator(
-       Arena* arena = nullptr) override;
+      Arena* arena = nullptr) override;
 
  private:
   friend class DynamicIterator;
@@ -265,36 +264,34 @@ class HashLinkListRep : public MemTableRep {
     explicit FullListIterator(MemtableSkipList* list, Allocator* allocator)
         : iter_(list), full_list_(list), allocator_(allocator) {}
 
-    virtual ~FullListIterator() {
+    ~FullListIterator() override {}
-    }
 
     // Returns true iff the iterator is positioned at a valid node.
-    virtual bool Valid() const override { return iter_.Valid(); }
+    bool Valid() const override { return iter_.Valid(); }
 
     // Returns the key at the current position.
     // REQUIRES: Valid()
-    virtual const char* key() const override {
+    const char* key() const override {
       assert(Valid());
       return iter_.key();
     }
 
     // Advances to the next position.
     // REQUIRES: Valid()
-    virtual void Next() override {
+    void Next() override {
       assert(Valid());
       iter_.Next();
     }
 
     // Advances to the previous position.
     // REQUIRES: Valid()
-    virtual void Prev() override {
+    void Prev() override {
       assert(Valid());
       iter_.Prev();
     }
 
     // Advance to the first entry with a key >= target
-    virtual void Seek(const Slice& internal_key,
+    void Seek(const Slice& internal_key, const char* memtable_key) override {
-                      const char* memtable_key) override {
       const char* encoded_key =
           (memtable_key != nullptr) ?
               memtable_key : EncodeKey(&tmp_, internal_key);
@@ -302,8 +299,8 @@ class HashLinkListRep : public MemTableRep {
     }
 
     // Retreat to the last entry with a key <= target
-    virtual void SeekForPrev(const Slice& internal_key,
+    void SeekForPrev(const Slice& internal_key,
-                             const char* memtable_key) override {
+                     const char* memtable_key) override {
       const char* encoded_key = (memtable_key != nullptr)
                                     ? memtable_key
                                     : EncodeKey(&tmp_, internal_key);
@@ -312,11 +309,12 @@ class HashLinkListRep : public MemTableRep {
 
     // Position at the first entry in collection.
     // Final state of iterator is Valid() iff collection is not empty.
-    virtual void SeekToFirst() override { iter_.SeekToFirst(); }
+    void SeekToFirst() override { iter_.SeekToFirst(); }
 
     // Position at the last entry in collection.
     // Final state of iterator is Valid() iff collection is not empty.
-    virtual void SeekToLast() override { iter_.SeekToLast(); }
+    void SeekToLast() override { iter_.SeekToLast(); }
+
    private:
     MemtableSkipList::Iterator iter_;
     // To destruct with the iterator.
@@ -333,43 +331,43 @@ class HashLinkListRep : public MemTableRep {
           head_(head),
           node_(nullptr) {}
 
-    virtual ~LinkListIterator() {}
+    ~LinkListIterator() override {}
 
     // Returns true iff the iterator is positioned at a valid node.
-    virtual bool Valid() const override { return node_ != nullptr; }
+    bool Valid() const override { return node_ != nullptr; }
 
     // Returns the key at the current position.
     // REQUIRES: Valid()
-    virtual const char* key() const override {
+    const char* key() const override {
       assert(Valid());
       return node_->key;
     }
 
     // Advances to the next position.
     // REQUIRES: Valid()
-    virtual void Next() override {
+    void Next() override {
       assert(Valid());
       node_ = node_->Next();
     }
 
     // Advances to the previous position.
     // REQUIRES: Valid()
-    virtual void Prev() override {
+    void Prev() override {
       // Prefix iterator does not support total order.
       // We simply set the iterator to invalid state
       Reset(nullptr);
     }
 
     // Advance to the first entry with a key >= target
-    virtual void Seek(const Slice& internal_key,
+    void Seek(const Slice& internal_key,
-                      const char* /*memtable_key*/) override {
+              const char* /*memtable_key*/) override {
       node_ = hash_link_list_rep_->FindGreaterOrEqualInBucket(head_,
                                                               internal_key);
     }
 
     // Retreat to the last entry with a key <= target
-    virtual void SeekForPrev(const Slice& /*internal_key*/,
+    void SeekForPrev(const Slice& /*internal_key*/,
-                             const char* /*memtable_key*/) override {
+                     const char* /*memtable_key*/) override {
       // Since we do not support Prev()
       // We simply do not support SeekForPrev
       Reset(nullptr);
@@ -377,7 +375,7 @@ class HashLinkListRep : public MemTableRep {
 
     // Position at the first entry in collection.
     // Final state of iterator is Valid() iff collection is not empty.
-    virtual void SeekToFirst() override {
+    void SeekToFirst() override {
       // Prefix iterator does not support total order.
       // We simply set the iterator to invalid state
       Reset(nullptr);
@@ -385,7 +383,7 @@ class HashLinkListRep : public MemTableRep {
 
     // Position at the last entry in collection.
     // Final state of iterator is Valid() iff collection is not empty.
-    virtual void SeekToLast() override {
+    void SeekToLast() override {
       // Prefix iterator does not support total order.
       // We simply set the iterator to invalid state
       Reset(nullptr);
@@ -414,7 +412,7 @@ class HashLinkListRep : public MemTableRep {
           memtable_rep_(memtable_rep) {}
 
     // Advance to the first entry with a key >= target
-    virtual void Seek(const Slice& k, const char* memtable_key) override {
+    void Seek(const Slice& k, const char* memtable_key) override {
       auto transformed = memtable_rep_.GetPrefix(k);
       auto* bucket = memtable_rep_.GetBucket(transformed);
 
@@ -443,21 +441,21 @@ class HashLinkListRep : public MemTableRep {
       }
     }
 
-    virtual bool Valid() const override {
+    bool Valid() const override {
       if (skip_list_iter_) {
         return skip_list_iter_->Valid();
       }
       return HashLinkListRep::LinkListIterator::Valid();
     }
 
-    virtual const char* key() const override {
+    const char* key() const override {
       if (skip_list_iter_) {
         return skip_list_iter_->key();
       }
       return HashLinkListRep::LinkListIterator::key();
     }
 
-    virtual void Next() override {
+    void Next() override {
       if (skip_list_iter_) {
         skip_list_iter_->Next();
       } else {
@@ -476,19 +474,19 @@ class HashLinkListRep : public MemTableRep {
     // instantiating an empty bucket over which to iterate.
    public:
     EmptyIterator() { }
-    virtual bool Valid() const override { return false; }
+    bool Valid() const override { return false; }
-    virtual const char* key() const override {
+    const char* key() const override {
       assert(false);
       return nullptr;
     }
-    virtual void Next() override {}
+    void Next() override {}
-    virtual void Prev() override {}
+    void Prev() override {}
-    virtual void Seek(const Slice& /*user_key*/,
+    void Seek(const Slice& /*user_key*/,
-                      const char* /*memtable_key*/) override {}
+              const char* /*memtable_key*/) override {}
-    virtual void SeekForPrev(const Slice& /*user_key*/,
+    void SeekForPrev(const Slice& /*user_key*/,
-                             const char* /*memtable_key*/) override {}
+                     const char* /*memtable_key*/) override {}
-    virtual void SeekToFirst() override {}
+    void SeekToFirst() override {}
-    virtual void SeekToLast() override {}
+    void SeekToLast() override {}
 
    private:
   };

memtable/hash_skiplist_rep.cc

@@ -28,21 +28,20 @@ class HashSkipListRep : public MemTableRep {
                   size_t bucket_size, int32_t skiplist_height,
                   int32_t skiplist_branching_factor);
 
-  virtual void Insert(KeyHandle handle) override;
+  void Insert(KeyHandle handle) override;
 
-  virtual bool Contains(const char* key) const override;
+  bool Contains(const char* key) const override;
 
-  virtual size_t ApproximateMemoryUsage() override;
+  size_t ApproximateMemoryUsage() override;
 
-  virtual void Get(const LookupKey& k, void* callback_args,
+  void Get(const LookupKey& k, void* callback_args,
-                   bool (*callback_func)(void* arg,
+           bool (*callback_func)(void* arg, const char* entry)) override;
-                                         const char* entry)) override;
 
-  virtual ~HashSkipListRep();
+  ~HashSkipListRep() override;
 
-  virtual MemTableRep::Iterator* GetIterator(Arena* arena = nullptr) override;
+  MemTableRep::Iterator* GetIterator(Arena* arena = nullptr) override;
 
-  virtual MemTableRep::Iterator* GetDynamicPrefixIterator(
+  MemTableRep::Iterator* GetDynamicPrefixIterator(
       Arena* arena = nullptr) override;
 
  private:
@@ -85,7 +84,7 @@ class HashSkipListRep : public MemTableRep {
                       Arena* arena = nullptr)
         : list_(list), iter_(list), own_list_(own_list), arena_(arena) {}
 
-    virtual ~Iterator() {
+    ~Iterator() override {
       // if we own the list, we should also delete it
       if (own_list_) {
         assert(list_ != nullptr);
@@ -94,34 +93,31 @@ class HashSkipListRep : public MemTableRep {
     }
 
     // Returns true iff the iterator is positioned at a valid node.
-    virtual bool Valid() const override {
+    bool Valid() const override { return list_ != nullptr && iter_.Valid(); }
-      return list_ != nullptr && iter_.Valid();
-    }
 
     // Returns the key at the current position.
     // REQUIRES: Valid()
-    virtual const char* key() const override {
+    const char* key() const override {
       assert(Valid());
       return iter_.key();
     }
 
     // Advances to the next position.
     // REQUIRES: Valid()
-    virtual void Next() override {
+    void Next() override {
       assert(Valid());
       iter_.Next();
     }
 
     // Advances to the previous position.
     // REQUIRES: Valid()
-    virtual void Prev() override {
+    void Prev() override {
       assert(Valid());
       iter_.Prev();
     }
 
     // Advance to the first entry with a key >= target
-    virtual void Seek(const Slice& internal_key,
+    void Seek(const Slice& internal_key, const char* memtable_key) override {
-                      const char* memtable_key) override {
       if (list_ != nullptr) {
         const char* encoded_key =
             (memtable_key != nullptr) ?
@@ -131,15 +127,15 @@ class HashSkipListRep : public MemTableRep {
     }
 
     // Retreat to the last entry with a key <= target
-    virtual void SeekForPrev(const Slice& /*internal_key*/,
+    void SeekForPrev(const Slice& /*internal_key*/,
-                             const char* /*memtable_key*/) override {
+                     const char* /*memtable_key*/) override {
       // not supported
       assert(false);
     }
 
     // Position at the first entry in collection.
     // Final state of iterator is Valid() iff collection is not empty.
-    virtual void SeekToFirst() override {
+    void SeekToFirst() override {
       if (list_ != nullptr) {
         iter_.SeekToFirst();
       }
@@ -147,11 +143,12 @@ class HashSkipListRep : public MemTableRep {
 
     // Position at the last entry in collection.
     // Final state of iterator is Valid() iff collection is not empty.
-    virtual void SeekToLast() override {
+    void SeekToLast() override {
       if (list_ != nullptr) {
         iter_.SeekToLast();
       }
     }
+
    protected:
     void Reset(Bucket* list) {
       if (own_list_) {
@@ -181,7 +178,7 @@ class HashSkipListRep : public MemTableRep {
         memtable_rep_(memtable_rep) {}
 
     // Advance to the first entry with a key >= target
-    virtual void Seek(const Slice& k, const char* memtable_key) override {
+    void Seek(const Slice& k, const char* memtable_key) override {
       auto transformed = memtable_rep_.transform_->Transform(ExtractUserKey(k));
       Reset(memtable_rep_.GetBucket(transformed));
       HashSkipListRep::Iterator::Seek(k, memtable_key);
@@ -189,7 +186,7 @@ class HashSkipListRep : public MemTableRep {
 
     // Position at the first entry in collection.
     // Final state of iterator is Valid() iff collection is not empty.
-    virtual void SeekToFirst() override {
+    void SeekToFirst() override {
       // Prefix iterator does not support total order.
       // We simply set the iterator to invalid state
       Reset(nullptr);
@@ -197,11 +194,12 @@ class HashSkipListRep : public MemTableRep {
 
     // Position at the last entry in collection.
     // Final state of iterator is Valid() iff collection is not empty.
-    virtual void SeekToLast() override {
+    void SeekToLast() override {
       // Prefix iterator does not support total order.
       // We simply set the iterator to invalid state
       Reset(nullptr);
     }
+
    private:
     // the underlying memtable
     const HashSkipListRep& memtable_rep_;
@@ -212,19 +210,19 @@ class HashSkipListRep : public MemTableRep {
     // instantiating an empty bucket over which to iterate.
    public:
     EmptyIterator() { }
-    virtual bool Valid() const override { return false; }
+    bool Valid() const override { return false; }
-    virtual const char* key() const override {
+    const char* key() const override {
       assert(false);
       return nullptr;
     }
-    virtual void Next() override {}
+    void Next() override {}
-    virtual void Prev() override {}
+    void Prev() override {}
-    virtual void Seek(const Slice& /*internal_key*/,
+    void Seek(const Slice& /*internal_key*/,
-                      const char* /*memtable_key*/) override {}
+              const char* /*memtable_key*/) override {}
-    virtual void SeekForPrev(const Slice& /*internal_key*/,
+    void SeekForPrev(const Slice& /*internal_key*/,
-                             const char* /*memtable_key*/) override {}
+                     const char* /*memtable_key*/) override {}
-    virtual void SeekToFirst() override {}
+    void SeekToFirst() override {}
-    virtual void SeekToLast() override {}
+    void SeekToLast() override {}
 
    private:
   };

memtable/skiplistrep.cc

@@ -27,57 +27,55 @@ public:
        transform_(transform),
        lookahead_(lookahead) {}
 
- virtual KeyHandle Allocate(const size_t len, char** buf) override {
+ KeyHandle Allocate(const size_t len, char** buf) override {
    *buf = skip_list_.AllocateKey(len);
    return static_cast<KeyHandle>(*buf);
-  }
+ }
 
   // Insert key into the list.
   // REQUIRES: nothing that compares equal to key is currently in the list.
-  virtual void Insert(KeyHandle handle) override {
+ void Insert(KeyHandle handle) override {
-    skip_list_.Insert(static_cast<char*>(handle));
+   skip_list_.Insert(static_cast<char*>(handle));
-  }
+ }
 
-  virtual bool InsertKey(KeyHandle handle) override {
+ bool InsertKey(KeyHandle handle) override {
-    return skip_list_.Insert(static_cast<char*>(handle));
+   return skip_list_.Insert(static_cast<char*>(handle));
-  }
+ }
 
-  virtual void InsertWithHint(KeyHandle handle, void** hint) override {
+ void InsertWithHint(KeyHandle handle, void** hint) override {
-    skip_list_.InsertWithHint(static_cast<char*>(handle), hint);
+   skip_list_.InsertWithHint(static_cast<char*>(handle), hint);
-  }
+ }
 
-  virtual bool InsertKeyWithHint(KeyHandle handle, void** hint) override {
+ bool InsertKeyWithHint(KeyHandle handle, void** hint) override {
-    return skip_list_.InsertWithHint(static_cast<char*>(handle), hint);
+   return skip_list_.InsertWithHint(static_cast<char*>(handle), hint);
-  }
+ }
 
-  virtual void InsertConcurrently(KeyHandle handle) override {
+ void InsertConcurrently(KeyHandle handle) override {
-    skip_list_.InsertConcurrently(static_cast<char*>(handle));
+   skip_list_.InsertConcurrently(static_cast<char*>(handle));
-  }
+ }
 
-  virtual bool InsertKeyConcurrently(KeyHandle handle) override {
+ bool InsertKeyConcurrently(KeyHandle handle) override {
-    return skip_list_.InsertConcurrently(static_cast<char*>(handle));
+   return skip_list_.InsertConcurrently(static_cast<char*>(handle));
-  }
+ }
 
   // Returns true iff an entry that compares equal to key is in the list.
-  virtual bool Contains(const char* key) const override {
+ bool Contains(const char* key) const override {
-    return skip_list_.Contains(key);
+   return skip_list_.Contains(key);
-  }
+ }
-
+
-  virtual size_t ApproximateMemoryUsage() override {
+ size_t ApproximateMemoryUsage() override {
-    // All memory is allocated through allocator; nothing to report here
+   // All memory is allocated through allocator; nothing to report here
-    return 0;
+   return 0;
-  }
+ }
-
+
-  virtual void Get(const LookupKey& k, void* callback_args,
+ void Get(const LookupKey& k, void* callback_args,
-                   bool (*callback_func)(void* arg,
+          bool (*callback_func)(void* arg, const char* entry)) override {
-                                         const char* entry)) override {
+   SkipListRep::Iterator iter(&skip_list_);
-    SkipListRep::Iterator iter(&skip_list_);
+   Slice dummy_slice;
-    Slice dummy_slice;
+   for (iter.Seek(dummy_slice, k.memtable_key().data());
-    for (iter.Seek(dummy_slice, k.memtable_key().data());
+        iter.Valid() && callback_func(callback_args, iter.key()); iter.Next()) {
-         iter.Valid() && callback_func(callback_args, iter.key());
+   }
-         iter.Next()) {
+ }
-    }
-  }
 
   uint64_t ApproximateNumEntries(const Slice& start_ikey,
                                  const Slice& end_ikey) override {
@@ -88,7 +86,7 @@ public:
     return (end_count >= start_count) ? (end_count - start_count) : 0;
   }
 
-  virtual ~SkipListRep() override { }
+  ~SkipListRep() override {}
 
   // Iteration over the contents of a skip list
   class Iterator : public MemTableRep::Iterator {
@@ -101,34 +99,25 @@ public:
         const InlineSkipList<const MemTableRep::KeyComparator&>* list)
         : iter_(list) {}
 
-    virtual ~Iterator() override { }
+    ~Iterator() override {}
 
     // Returns true iff the iterator is positioned at a valid node.
-    virtual bool Valid() const override {
+    bool Valid() const override { return iter_.Valid(); }
-      return iter_.Valid();
-    }
 
     // Returns the key at the current position.
     // REQUIRES: Valid()
-    virtual const char* key() const override {
+    const char* key() const override { return iter_.key(); }
-      return iter_.key();
-    }
 
     // Advances to the next position.
     // REQUIRES: Valid()
-    virtual void Next() override {
+    void Next() override { iter_.Next(); }
-      iter_.Next();
-    }
 
     // Advances to the previous position.
     // REQUIRES: Valid()
-    virtual void Prev() override {
+    void Prev() override { iter_.Prev(); }
-      iter_.Prev();
-    }
 
     // Advance to the first entry with a key >= target
-    virtual void Seek(const Slice& user_key, const char* memtable_key)
+    void Seek(const Slice& user_key, const char* memtable_key) override {
-        override {
       if (memtable_key != nullptr) {
         iter_.Seek(memtable_key);
       } else {
@@ -137,8 +126,7 @@ public:
     }
 
     // Retreat to the last entry with a key <= target
-    virtual void SeekForPrev(const Slice& user_key,
+    void SeekForPrev(const Slice& user_key, const char* memtable_key) override {
-                             const char* memtable_key) override {
       if (memtable_key != nullptr) {
         iter_.SeekForPrev(memtable_key);
       } else {
@@ -148,15 +136,12 @@ public:
 
     // Position at the first entry in list.
     // Final state of iterator is Valid() iff list is not empty.
-    virtual void SeekToFirst() override {
+    void SeekToFirst() override { iter_.SeekToFirst(); }
-      iter_.SeekToFirst();
-    }
 
     // Position at the last entry in list.
     // Final state of iterator is Valid() iff list is not empty.
-    virtual void SeekToLast() override {
+    void SeekToLast() override { iter_.SeekToLast(); }
-      iter_.SeekToLast();
+
-    }
    protected:
     std::string tmp_;       // For passing to EncodeKey
   };
@@ -170,18 +155,16 @@ public:
     explicit LookaheadIterator(const SkipListRep& rep) :
         rep_(rep), iter_(&rep_.skip_list_), prev_(iter_) {}
 
-    virtual ~LookaheadIterator() override {}
+    ~LookaheadIterator() override {}
 
-    virtual bool Valid() const override {
+    bool Valid() const override { return iter_.Valid(); }
-      return iter_.Valid();
-    }
 
-    virtual const char *key() const override {
+    const char* key() const override {
       assert(Valid());
       return iter_.key();
     }
 
-    virtual void Next() override {
+    void Next() override {
       assert(Valid());
 
       bool advance_prev = true;
@@ -206,14 +189,13 @@ public:
       iter_.Next();
     }
 
-    virtual void Prev() override {
+    void Prev() override {
       assert(Valid());
       iter_.Prev();
       prev_ = iter_;
     }
 
-    virtual void Seek(const Slice& internal_key, const char *memtable_key)
+    void Seek(const Slice& internal_key, const char* memtable_key) override {
-        override {
       const char *encoded_key =
         (memtable_key != nullptr) ?
             memtable_key : EncodeKey(&tmp_, internal_key);
@@ -236,8 +218,8 @@ public:
       prev_ = iter_;
     }
 
-    virtual void SeekForPrev(const Slice& internal_key,
+    void SeekForPrev(const Slice& internal_key,
-                             const char* memtable_key) override {
+                     const char* memtable_key) override {
       const char* encoded_key = (memtable_key != nullptr)
                                     ? memtable_key
                                     : EncodeKey(&tmp_, internal_key);
@@ -245,12 +227,12 @@ public:
       prev_ = iter_;
     }
 
-    virtual void SeekToFirst() override {
+    void SeekToFirst() override {
       iter_.SeekToFirst();
       prev_ = iter_;
     }
 
-    virtual void SeekToLast() override {
+    void SeekToLast() override {
       iter_.SeekToLast();
       prev_ = iter_;
     }
@@ -264,7 +246,7 @@ public:
     InlineSkipList<const MemTableRep::KeyComparator&>::Iterator prev_;
   };
 
-  virtual MemTableRep::Iterator* GetIterator(Arena* arena = nullptr) override {
+  MemTableRep::Iterator* GetIterator(Arena* arena = nullptr) override {
     if (lookahead_ > 0) {
       void *mem =
         arena ? arena->AllocateAligned(sizeof(SkipListRep::LookaheadIterator))

memtable/vectorrep.cc

@@ -31,20 +31,19 @@ class VectorRep : public MemTableRep {
   // single buffer and pass that in as the parameter to Insert)
   // REQUIRES: nothing that compares equal to key is currently in the
   // collection.
-  virtual void Insert(KeyHandle handle) override;
+  void Insert(KeyHandle handle) override;
 
   // Returns true iff an entry that compares equal to key is in the collection.
-  virtual bool Contains(const char* key) const override;
+  bool Contains(const char* key) const override;
 
-  virtual void MarkReadOnly() override;
+  void MarkReadOnly() override;
 
-  virtual size_t ApproximateMemoryUsage() override;
+  size_t ApproximateMemoryUsage() override;
 
-  virtual void Get(const LookupKey& k, void* callback_args,
+  void Get(const LookupKey& k, void* callback_args,
-                   bool (*callback_func)(void* arg,
+           bool (*callback_func)(void* arg, const char* entry)) override;
-                                         const char* entry)) override;
 
-  virtual ~VectorRep() override { }
+  ~VectorRep() override {}
 
   class Iterator : public MemTableRep::Iterator {
     class VectorRep* vrep_;
@@ -62,41 +61,40 @@ class VectorRep : public MemTableRep {
     // Initialize an iterator over the specified collection.
     // The returned iterator is not valid.
     // explicit Iterator(const MemTableRep* collection);
-    virtual ~Iterator() override { };
+    ~Iterator() override{};
 
     // Returns true iff the iterator is positioned at a valid node.
-    virtual bool Valid() const override;
+    bool Valid() const override;
 
     // Returns the key at the current position.
     // REQUIRES: Valid()
-    virtual const char* key() const override;
+    const char* key() const override;
 
     // Advances to the next position.
     // REQUIRES: Valid()
-    virtual void Next() override;
+    void Next() override;
 
     // Advances to the previous position.
     // REQUIRES: Valid()
-    virtual void Prev() override;
+    void Prev() override;
 
     // Advance to the first entry with a key >= target
-    virtual void Seek(const Slice& user_key, const char* memtable_key) override;
+    void Seek(const Slice& user_key, const char* memtable_key) override;
 
     // Advance to the first entry with a key <= target
-    virtual void SeekForPrev(const Slice& user_key,
+    void SeekForPrev(const Slice& user_key, const char* memtable_key) override;
-                             const char* memtable_key) override;
 
     // Position at the first entry in collection.
     // Final state of iterator is Valid() iff collection is not empty.
-    virtual void SeekToFirst() override;
+    void SeekToFirst() override;
 
     // Position at the last entry in collection.
     // Final state of iterator is Valid() iff collection is not empty.
-    virtual void SeekToLast() override;
+    void SeekToLast() override;
   };
 
   // Return an iterator over the keys in this representation.
-  virtual MemTableRep::Iterator* GetIterator(Arena* arena) override;
+  MemTableRep::Iterator* GetIterator(Arena* arena) override;
 
  private:
   friend class Iterator;

table/block_based_filter_block_test.cc

@@ -21,18 +21,16 @@ namespace rocksdb {
 // For testing: emit an array with one hash value per key
 class TestHashFilter : public FilterPolicy {
  public:
-  virtual const char* Name() const override { return "TestHashFilter"; }
+  const char* Name() const override { return "TestHashFilter"; }
 
-  virtual void CreateFilter(const Slice* keys, int n,
+  void CreateFilter(const Slice* keys, int n, std::string* dst) const override {
-                            std::string* dst) const override {
     for (int i = 0; i < n; i++) {
       uint32_t h = Hash(keys[i].data(), keys[i].size(), 1);
       PutFixed32(dst, h);
     }
   }
 
-  virtual bool KeyMayMatch(const Slice& key,
+  bool KeyMayMatch(const Slice& key, const Slice& filter) const override {
-                           const Slice& filter) const override {
     uint32_t h = Hash(key.data(), key.size(), 1);
     for (unsigned int i = 0; i + 4 <= filter.size(); i += 4) {
       if (h == DecodeFixed32(filter.data() + i)) {
@@ -146,7 +144,7 @@ class BlockBasedFilterBlockTest : public testing::Test {
     table_options_.filter_policy.reset(NewBloomFilterPolicy(10));
   }
 
-  ~BlockBasedFilterBlockTest() {}
+  ~BlockBasedFilterBlockTest() override {}
 };
 
 TEST_F(BlockBasedFilterBlockTest, BlockBasedEmptyBuilder) {

table/block_based_table_builder.cc

@@ -210,14 +210,14 @@ class BlockBasedTableBuilder::BlockBasedTablePropertiesCollector
         whole_key_filtering_(whole_key_filtering),
         prefix_filtering_(prefix_filtering) {}
 
-  virtual Status InternalAdd(const Slice& /*key*/, const Slice& /*value*/,
+  Status InternalAdd(const Slice& /*key*/, const Slice& /*value*/,
-                             uint64_t /*file_size*/) override {
+                     uint64_t /*file_size*/) override {
     // Intentionally left blank. Have no interest in collecting stats for
     // individual key/value pairs.
     return Status::OK();
   }
 
-  virtual Status Finish(UserCollectedProperties* properties) override {
+  Status Finish(UserCollectedProperties* properties) override {
     std::string val;
     PutFixed32(&val, static_cast<uint32_t>(index_type_));
     properties->insert({BlockBasedTablePropertyNames::kIndexType, val});
@@ -229,11 +229,11 @@ class BlockBasedTableBuilder::BlockBasedTablePropertiesCollector
   }
 
   // The name of the properties collector can be used for debugging purpose.
-  virtual const char* Name() const override {
+  const char* Name() const override {
     return "BlockBasedTablePropertiesCollector";
   }
 
-  virtual UserCollectedProperties GetReadableProperties() const override {
+  UserCollectedProperties GetReadableProperties() const override {
     // Intentionally left blank.
     return UserCollectedProperties();
   }

table/block_based_table_reader.cc

@@ -259,7 +259,7 @@ class PartitionIndexReader : public IndexReader, public Cleanable {
   }
 
   // return a two-level iterator: first level is on the partition index
-  virtual InternalIteratorBase<BlockHandle>* NewIterator(
+  InternalIteratorBase<BlockHandle>* NewIterator(
       IndexBlockIter* /*iter*/ = nullptr, bool /*dont_care*/ = true,
       bool fill_cache = true) override {
     Statistics* kNullStats = nullptr;
@@ -294,7 +294,7 @@ class PartitionIndexReader : public IndexReader, public Cleanable {
     // in its destructor.
   }
 
-  virtual void CacheDependencies(bool pin) override {
+  void CacheDependencies(bool pin) override {
     // Before read partitions, prefetch them to avoid lots of IOs
     auto rep = table_->rep_;
     IndexBlockIter biter;
@@ -362,12 +362,10 @@ class PartitionIndexReader : public IndexReader, public Cleanable {
     }
   }
 
-  virtual size_t size() const override { return index_block_->size(); }
+  size_t size() const override { return index_block_->size(); }
-  virtual size_t usable_size() const override {
+  size_t usable_size() const override { return index_block_->usable_size(); }
-    return index_block_->usable_size();
-  }
 
-  virtual size_t ApproximateMemoryUsage() const override {
+  size_t ApproximateMemoryUsage() const override {
     assert(index_block_);
     size_t usage = index_block_->ApproximateMemoryUsage();
 #ifdef ROCKSDB_MALLOC_USABLE_SIZE
@@ -436,7 +434,7 @@ class BinarySearchIndexReader : public IndexReader {
     return s;
   }
 
-  virtual InternalIteratorBase<BlockHandle>* NewIterator(
+  InternalIteratorBase<BlockHandle>* NewIterator(
       IndexBlockIter* iter = nullptr, bool /*dont_care*/ = true,
       bool /*dont_care*/ = true) override {
     Statistics* kNullStats = nullptr;
@@ -447,12 +445,10 @@ class BinarySearchIndexReader : public IndexReader {
         index_key_includes_seq_, index_value_is_full_);
   }
 
-  virtual size_t size() const override { return index_block_->size(); }
+  size_t size() const override { return index_block_->size(); }
-  virtual size_t usable_size() const override {
+  size_t usable_size() const override { return index_block_->usable_size(); }
-    return index_block_->usable_size();
-  }
 
-  virtual size_t ApproximateMemoryUsage() const override {
+  size_t ApproximateMemoryUsage() const override {
     assert(index_block_);
     size_t usage = index_block_->ApproximateMemoryUsage();
 #ifdef ROCKSDB_MALLOC_USABLE_SIZE
@@ -566,7 +562,7 @@ class HashIndexReader : public IndexReader {
     return Status::OK();
   }
 
-  virtual InternalIteratorBase<BlockHandle>* NewIterator(
+  InternalIteratorBase<BlockHandle>* NewIterator(
       IndexBlockIter* iter = nullptr, bool total_order_seek = true,
       bool /*dont_care*/ = true) override {
     Statistics* kNullStats = nullptr;
@@ -578,12 +574,10 @@ class HashIndexReader : public IndexReader {
         false /* block_contents_pinned */, prefix_index_.get());
   }
 
-  virtual size_t size() const override { return index_block_->size(); }
+  size_t size() const override { return index_block_->size(); }
-  virtual size_t usable_size() const override {
+  size_t usable_size() const override { return index_block_->usable_size(); }
-    return index_block_->usable_size();
-  }
 
-  virtual size_t ApproximateMemoryUsage() const override {
+  size_t ApproximateMemoryUsage() const override {
     assert(index_block_);
     size_t usage = index_block_->ApproximateMemoryUsage();
     usage += prefixes_contents_.usable_size();
@@ -610,7 +604,7 @@ class HashIndexReader : public IndexReader {
     assert(index_block_ != nullptr);
   }
 
-  ~HashIndexReader() {}
+  ~HashIndexReader() override {}
 
   std::unique_ptr<Block> index_block_;
   std::unique_ptr<BlockPrefixIndex> prefix_index_;

table/cuckoo_table_reader.cc

@@ -197,7 +197,7 @@ void CuckooTableReader::Prepare(const Slice& key) {
 class CuckooTableIterator : public InternalIterator {
  public:
   explicit CuckooTableIterator(CuckooTableReader* reader);
-  ~CuckooTableIterator() {}
+  ~CuckooTableIterator() override {}
   bool Valid() const override;
   void SeekToFirst() override;
   void SeekToLast() override;

table/flush_block_policy.cc

@@ -30,8 +30,7 @@ class FlushBlockBySizePolicy : public FlushBlockPolicy {
         align_(align),
         data_block_builder_(data_block_builder) {}
 
-  virtual bool Update(const Slice& key,
+  bool Update(const Slice& key, const Slice& value) override {
-                      const Slice& value) override {
     // it makes no sense to flush when the data block is empty
     if (data_block_builder_.empty()) {
       return false;

table/full_filter_block_test.cc

@@ -20,12 +20,12 @@ class TestFilterBitsBuilder : public FilterBitsBuilder {
   explicit TestFilterBitsBuilder() {}
 
   // Add Key to filter
-  virtual void AddKey(const Slice& key) override {
+  void AddKey(const Slice& key) override {
     hash_entries_.push_back(Hash(key.data(), key.size(), 1));
   }
 
   // Generate the filter using the keys that are added
-  virtual Slice Finish(std::unique_ptr<const char[]>* buf) override {
+  Slice Finish(std::unique_ptr<const char[]>* buf) override {
     uint32_t len = static_cast<uint32_t>(hash_entries_.size()) * 4;
     char* data = new char[len];
     for (size_t i = 0; i < hash_entries_.size(); i++) {
@@ -45,7 +45,7 @@ class TestFilterBitsReader : public FilterBitsReader {
   explicit TestFilterBitsReader(const Slice& contents)
       : data_(contents.data()), len_(static_cast<uint32_t>(contents.size())) {}
 
-  virtual bool MayMatch(const Slice& entry) override {
+  bool MayMatch(const Slice& entry) override {
     uint32_t h = Hash(entry.data(), entry.size(), 1);
     for (size_t i = 0; i + 4 <= len_; i += 4) {
       if (h == DecodeFixed32(data_ + i)) {
@@ -63,18 +63,16 @@ class TestFilterBitsReader : public FilterBitsReader {
 
 class TestHashFilter : public FilterPolicy {
  public:
-  virtual const char* Name() const override { return "TestHashFilter"; }
+  const char* Name() const override { return "TestHashFilter"; }
 
-  virtual void CreateFilter(const Slice* keys, int n,
+  void CreateFilter(const Slice* keys, int n, std::string* dst) const override {
-                            std::string* dst) const override {
     for (int i = 0; i < n; i++) {
       uint32_t h = Hash(keys[i].data(), keys[i].size(), 1);
       PutFixed32(dst, h);
     }
   }
 
-  virtual bool KeyMayMatch(const Slice& key,
+  bool KeyMayMatch(const Slice& key, const Slice& filter) const override {
-                           const Slice& filter) const override {
     uint32_t h = Hash(key.data(), key.size(), 1);
     for (unsigned int i = 0; i + 4 <= filter.size(); i += 4) {
       if (h == DecodeFixed32(filter.data() + i)) {
@@ -84,12 +82,11 @@ class TestHashFilter : public FilterPolicy {
     return false;
   }
 
-  virtual FilterBitsBuilder* GetFilterBitsBuilder() const override {
+  FilterBitsBuilder* GetFilterBitsBuilder() const override {
     return new TestFilterBitsBuilder();
   }
 
-  virtual FilterBitsReader* GetFilterBitsReader(const Slice& contents)
+  FilterBitsReader* GetFilterBitsReader(const Slice& contents) const override {
-      const override {
     return new TestFilterBitsReader(contents);
   }
 };
@@ -145,7 +142,7 @@ class FullFilterBlockTest : public testing::Test {
     table_options_.filter_policy.reset(NewBloomFilterPolicy(10, false));
   }
 
-  ~FullFilterBlockTest() {}
+  ~FullFilterBlockTest() override {}
 };
 
 TEST_F(FullFilterBlockTest, EmptyBuilder) {

table/iterator.cc

@@ -110,13 +110,13 @@ namespace {
 class EmptyIterator : public Iterator {
  public:
   explicit EmptyIterator(const Status& s) : status_(s) { }
-  virtual bool Valid() const override { return false; }
+  bool Valid() const override { return false; }
-  virtual void Seek(const Slice& /*target*/) override {}
+  void Seek(const Slice& /*target*/) override {}
-  virtual void SeekForPrev(const Slice& /*target*/) override {}
+  void SeekForPrev(const Slice& /*target*/) override {}
-  virtual void SeekToFirst() override {}
+  void SeekToFirst() override {}
-  virtual void SeekToLast() override {}
+  void SeekToLast() override {}
-  virtual void Next() override { assert(false); }
+  void Next() override { assert(false); }
-  virtual void Prev() override { assert(false); }
+  void Prev() override { assert(false); }
   Slice key() const override {
     assert(false);
     return Slice();
@@ -125,7 +125,7 @@ class EmptyIterator : public Iterator {
     assert(false);
     return Slice();
   }
-  virtual Status status() const override { return status_; }
+  Status status() const override { return status_; }
 
  private:
   Status status_;
@@ -135,13 +135,13 @@ template <class TValue = Slice>
 class EmptyInternalIterator : public InternalIteratorBase<TValue> {
  public:
   explicit EmptyInternalIterator(const Status& s) : status_(s) {}
-  virtual bool Valid() const override { return false; }
+  bool Valid() const override { return false; }
-  virtual void Seek(const Slice& /*target*/) override {}
+  void Seek(const Slice& /*target*/) override {}
-  virtual void SeekForPrev(const Slice& /*target*/) override {}
+  void SeekForPrev(const Slice& /*target*/) override {}
-  virtual void SeekToFirst() override {}
+  void SeekToFirst() override {}
-  virtual void SeekToLast() override {}
+  void SeekToLast() override {}
-  virtual void Next() override { assert(false); }
+  void Next() override { assert(false); }
-  virtual void Prev() override { assert(false); }
+  void Prev() override { assert(false); }
   Slice key() const override {
     assert(false);
     return Slice();
@@ -150,7 +150,7 @@ class EmptyInternalIterator : public InternalIteratorBase<TValue> {
     assert(false);
     return TValue();
   }
-  virtual Status status() const override { return status_; }
+  Status status() const override { return status_; }
 
  private:
   Status status_;

table/merger_test.cc

@@ -19,7 +19,7 @@ class MergerTest : public testing::Test {
         rnd_(3),
         merging_iterator_(nullptr),
         single_iterator_(nullptr) {}
-  ~MergerTest() = default;
+  ~MergerTest() override = default;
   std::vector<std::string> GenerateStrings(size_t len, int string_len) {
     std::vector<std::string> ret;
 

table/merging_iterator.cc

@@ -83,19 +83,17 @@ class MergingIterator : public InternalIterator {
     }
   }
 
-  virtual ~MergingIterator() {
+  ~MergingIterator() override {
     for (auto& child : children_) {
       child.DeleteIter(is_arena_mode_);
     }
   }
 
-  virtual bool Valid() const override {
+  bool Valid() const override { return current_ != nullptr && status_.ok(); }
-    return current_ != nullptr && status_.ok();
-  }
 
-  virtual Status status() const override { return status_; }
+  Status status() const override { return status_; }
 
-  virtual void SeekToFirst() override {
+  void SeekToFirst() override {
     ClearHeaps();
     status_ = Status::OK();
     for (auto& child : children_) {
@@ -111,7 +109,7 @@ class MergingIterator : public InternalIterator {
     current_ = CurrentForward();
   }
 
-  virtual void SeekToLast() override {
+  void SeekToLast() override {
     ClearHeaps();
     InitMaxHeap();
     status_ = Status::OK();
@@ -128,7 +126,7 @@ class MergingIterator : public InternalIterator {
     current_ = CurrentReverse();
   }
 
-  virtual void Seek(const Slice& target) override {
+  void Seek(const Slice& target) override {
     ClearHeaps();
     status_ = Status::OK();
     for (auto& child : children_) {
@@ -153,7 +151,7 @@ class MergingIterator : public InternalIterator {
     }
   }
 
-  virtual void SeekForPrev(const Slice& target) override {
+  void SeekForPrev(const Slice& target) override {
     ClearHeaps();
     InitMaxHeap();
     status_ = Status::OK();
@@ -180,7 +178,7 @@ class MergingIterator : public InternalIterator {
     }
   }
 
-  virtual void Next() override {
+  void Next() override {
     assert(Valid());
 
     // Ensure that all children are positioned after key().
@@ -214,7 +212,7 @@ class MergingIterator : public InternalIterator {
     current_ = CurrentForward();
   }
 
-  virtual void Prev() override {
+  void Prev() override {
     assert(Valid());
     // Ensure that all children are positioned before key().
     // If we are moving in the reverse direction, it is already
@@ -273,31 +271,30 @@ class MergingIterator : public InternalIterator {
     current_ = CurrentReverse();
   }
 
-  virtual Slice key() const override {
+  Slice key() const override {
     assert(Valid());
     return current_->key();
   }
 
-  virtual Slice value() const override {
+  Slice value() const override {
     assert(Valid());
     return current_->value();
   }
 
-  virtual void SetPinnedItersMgr(
+  void SetPinnedItersMgr(PinnedIteratorsManager* pinned_iters_mgr) override {
-      PinnedIteratorsManager* pinned_iters_mgr) override {
     pinned_iters_mgr_ = pinned_iters_mgr;
     for (auto& child : children_) {
       child.SetPinnedItersMgr(pinned_iters_mgr);
     }
   }
 
-  virtual bool IsKeyPinned() const override {
+  bool IsKeyPinned() const override {
     assert(Valid());
     return pinned_iters_mgr_ && pinned_iters_mgr_->PinningEnabled() &&
            current_->IsKeyPinned();
   }
 
-  virtual bool IsValuePinned() const override {
+  bool IsValuePinned() const override {
     assert(Valid());
     return pinned_iters_mgr_ && pinned_iters_mgr_->PinningEnabled() &&
            current_->IsValuePinned();

table/partitioned_filter_block_test.cc

@@ -27,7 +27,7 @@ class MockedBlockBasedTable : public BlockBasedTable {
     rep->cache_key_prefix_size = 10;
   }
 
-  virtual CachableEntry<FilterBlockReader> GetFilter(
+  CachableEntry<FilterBlockReader> GetFilter(
       FilePrefetchBuffer*, const BlockHandle& filter_blk_handle,
       const bool /* unused */, bool /* unused */, GetContext* /* unused */,
       const SliceTransform* prefix_extractor) const override {
@@ -38,7 +38,7 @@ class MockedBlockBasedTable : public BlockBasedTable {
     return {obj, nullptr};
   }
 
-  virtual FilterBlockReader* ReadFilter(
+  FilterBlockReader* ReadFilter(
       FilePrefetchBuffer*, const BlockHandle& filter_blk_handle,
       const bool /* unused */,
       const SliceTransform* prefix_extractor) const override {
@@ -67,7 +67,7 @@ class PartitionedFilterBlockTest
   }
 
   std::shared_ptr<Cache> cache_;
-  ~PartitionedFilterBlockTest() {}
+  ~PartitionedFilterBlockTest() override {}
 
   const std::string keys[4] = {"afoo", "bar", "box", "hello"};
   const std::string missing_keys[2] = {"missing", "other"};

table/plain_table_reader.cc

@@ -54,7 +54,7 @@ inline uint32_t GetFixed32Element(const char* base, size_t offset) {
 class PlainTableIterator : public InternalIterator {
  public:
   explicit PlainTableIterator(PlainTableReader* table, bool use_prefix_seek);
-  ~PlainTableIterator();
+  ~PlainTableIterator() override;
 
   bool Valid() const override;
 

table/table_test.cc

@@ -65,17 +65,17 @@ namespace {
 // DummyPropertiesCollector used to test BlockBasedTableProperties
 class DummyPropertiesCollector : public TablePropertiesCollector {
  public:
-  const char* Name() const { return ""; }
+  const char* Name() const override { return ""; }
 
-  Status Finish(UserCollectedProperties* /*properties*/) {
+  Status Finish(UserCollectedProperties* /*properties*/) override {
     return Status::OK();
   }
 
-  Status Add(const Slice& /*user_key*/, const Slice& /*value*/) {
+  Status Add(const Slice& /*user_key*/, const Slice& /*value*/) override {
     return Status::OK();
   }
 
-  virtual UserCollectedProperties GetReadableProperties() const {
+  UserCollectedProperties GetReadableProperties() const override {
     return UserCollectedProperties{};
   }
 };
@@ -83,21 +83,21 @@ class DummyPropertiesCollector : public TablePropertiesCollector {
 class DummyPropertiesCollectorFactory1
     : public TablePropertiesCollectorFactory {
  public:
-  virtual TablePropertiesCollector* CreateTablePropertiesCollector(
+  TablePropertiesCollector* CreateTablePropertiesCollector(
-      TablePropertiesCollectorFactory::Context /*context*/) {
+      TablePropertiesCollectorFactory::Context /*context*/) override {
     return new DummyPropertiesCollector();
   }
-  const char* Name() const { return "DummyPropertiesCollector1"; }
+  const char* Name() const override { return "DummyPropertiesCollector1"; }
 };
 
 class DummyPropertiesCollectorFactory2
     : public TablePropertiesCollectorFactory {
  public:
-  virtual TablePropertiesCollector* CreateTablePropertiesCollector(
+  TablePropertiesCollector* CreateTablePropertiesCollector(
-      TablePropertiesCollectorFactory::Context /*context*/) {
+      TablePropertiesCollectorFactory::Context /*context*/) override {
     return new DummyPropertiesCollector();
   }
-  const char* Name() const { return "DummyPropertiesCollector2"; }
+  const char* Name() const override { return "DummyPropertiesCollector2"; }
 };
 
 // Return reverse of "key".
@@ -110,23 +110,23 @@ std::string Reverse(const Slice& key) {
 
 class ReverseKeyComparator : public Comparator {
  public:
-  virtual const char* Name() const override {
+  const char* Name() const override {
     return "rocksdb.ReverseBytewiseComparator";
   }
 
-  virtual int Compare(const Slice& a, const Slice& b) const override {
+  int Compare(const Slice& a, const Slice& b) const override {
     return BytewiseComparator()->Compare(Reverse(a), Reverse(b));
   }
 
-  virtual void FindShortestSeparator(std::string* start,
+  void FindShortestSeparator(std::string* start,
-                                     const Slice& limit) const override {
+                             const Slice& limit) const override {
     std::string s = Reverse(*start);
     std::string l = Reverse(limit);
     BytewiseComparator()->FindShortestSeparator(&s, l);
     *start = Reverse(s);
   }
 
-  virtual void FindShortSuccessor(std::string* key) const override {
+  void FindShortSuccessor(std::string* key) const override {
     std::string s = Reverse(*key);
     BytewiseComparator()->FindShortSuccessor(&s);
     *key = Reverse(s);
@@ -212,15 +212,13 @@ class BlockConstructor: public Constructor {
       : Constructor(cmp),
         comparator_(cmp),
         block_(nullptr) { }
-  ~BlockConstructor() {
+  ~BlockConstructor() override { delete block_; }
-    delete block_;
+  Status FinishImpl(const Options& /*options*/,
-  }
+                    const ImmutableCFOptions& /*ioptions*/,
-  virtual Status FinishImpl(
+                    const MutableCFOptions& /*moptions*/,
-      const Options& /*options*/, const ImmutableCFOptions& /*ioptions*/,
+                    const BlockBasedTableOptions& table_options,
-      const MutableCFOptions& /*moptions*/,
+                    const InternalKeyComparator& /*internal_comparator*/,
-      const BlockBasedTableOptions& table_options,
+                    const stl_wrappers::KVMap& kv_map) override {
-      const InternalKeyComparator& /*internal_comparator*/,
-      const stl_wrappers::KVMap& kv_map) override {
     delete block_;
     block_ = nullptr;
     BlockBuilder builder(table_options.block_restart_interval);
@@ -235,7 +233,7 @@ class BlockConstructor: public Constructor {
     block_ = new Block(std::move(contents), kDisableGlobalSequenceNumber);
     return Status::OK();
   }
-  virtual InternalIterator* NewIterator(
+  InternalIterator* NewIterator(
       const SliceTransform* /*prefix_extractor*/) const override {
     return block_->NewIterator<DataBlockIter>(comparator_, comparator_);
   }
@@ -254,32 +252,32 @@ class KeyConvertingIterator : public InternalIterator {
   explicit KeyConvertingIterator(InternalIterator* iter,
                                  bool arena_mode = false)
       : iter_(iter), arena_mode_(arena_mode) {}
-  virtual ~KeyConvertingIterator() {
+  ~KeyConvertingIterator() override {
     if (arena_mode_) {
       iter_->~InternalIterator();
     } else {
       delete iter_;
     }
   }
-  virtual bool Valid() const override { return iter_->Valid() && status_.ok(); }
+  bool Valid() const override { return iter_->Valid() && status_.ok(); }
-  virtual void Seek(const Slice& target) override {
+  void Seek(const Slice& target) override {
     ParsedInternalKey ikey(target, kMaxSequenceNumber, kTypeValue);
     std::string encoded;
     AppendInternalKey(&encoded, ikey);
     iter_->Seek(encoded);
   }
-  virtual void SeekForPrev(const Slice& target) override {
+  void SeekForPrev(const Slice& target) override {
     ParsedInternalKey ikey(target, kMaxSequenceNumber, kTypeValue);
     std::string encoded;
     AppendInternalKey(&encoded, ikey);
     iter_->SeekForPrev(encoded);
   }
-  virtual void SeekToFirst() override { iter_->SeekToFirst(); }
+  void SeekToFirst() override { iter_->SeekToFirst(); }
-  virtual void SeekToLast() override { iter_->SeekToLast(); }
+  void SeekToLast() override { iter_->SeekToLast(); }
-  virtual void Next() override { iter_->Next(); }
+  void Next() override { iter_->Next(); }
-  virtual void Prev() override { iter_->Prev(); }
+  void Prev() override { iter_->Prev(); }
 
-  virtual Slice key() const override {
+  Slice key() const override {
     assert(Valid());
     ParsedInternalKey parsed_key;
     if (!ParseInternalKey(iter_->key(), &parsed_key)) {
@@ -289,8 +287,8 @@ class KeyConvertingIterator : public InternalIterator {
     return parsed_key.user_key;
   }
 
-  virtual Slice value() const override { return iter_->value(); }
+  Slice value() const override { return iter_->value(); }
-  virtual Status status() const override {
+  Status status() const override {
     return status_.ok() ? iter_->status() : status_;
   }
 
@@ -312,14 +310,13 @@ class TableConstructor: public Constructor {
       : Constructor(cmp),
         convert_to_internal_key_(convert_to_internal_key),
         level_(level) {}
-  ~TableConstructor() { Reset(); }
+  ~TableConstructor() override { Reset(); }
 
-  virtual Status FinishImpl(const Options& options,
+  Status FinishImpl(const Options& options, const ImmutableCFOptions& ioptions,
-                            const ImmutableCFOptions& ioptions,
+                    const MutableCFOptions& moptions,
-                            const MutableCFOptions& moptions,
+                    const BlockBasedTableOptions& /*table_options*/,
-                            const BlockBasedTableOptions& /*table_options*/,
+                    const InternalKeyComparator& internal_comparator,
-                            const InternalKeyComparator& internal_comparator,
+                    const stl_wrappers::KVMap& kv_map) override {
-                            const stl_wrappers::KVMap& kv_map) override {
     Reset();
     soptions.use_mmap_reads = ioptions.allow_mmap_reads;
     file_writer_.reset(test::GetWritableFileWriter(new test::StringSink(),
@@ -368,7 +365,7 @@ class TableConstructor: public Constructor {
         &table_reader_);
   }
 
-  virtual InternalIterator* NewIterator(
+  InternalIterator* NewIterator(
       const SliceTransform* prefix_extractor) const override {
     ReadOptions ro;
     InternalIterator* iter = table_reader_->NewIterator(ro, prefix_extractor);
@@ -401,7 +398,7 @@ class TableConstructor: public Constructor {
 
   virtual TableReader* GetTableReader() { return table_reader_.get(); }
 
-  virtual bool AnywayDeleteIterator() const override {
+  bool AnywayDeleteIterator() const override {
     return convert_to_internal_key_;
   }
 
@@ -449,15 +446,12 @@ class MemTableConstructor: public Constructor {
                      wb, kMaxSequenceNumber, 0 /* column_family_id */);
     memtable_->Ref();
   }
-  ~MemTableConstructor() {
+  ~MemTableConstructor() override { delete memtable_->Unref(); }
-    delete memtable_->Unref();
+  Status FinishImpl(const Options&, const ImmutableCFOptions& ioptions,
-  }
+                    const MutableCFOptions& /*moptions*/,
-  virtual Status FinishImpl(
+                    const BlockBasedTableOptions& /*table_options*/,
-      const Options&, const ImmutableCFOptions& ioptions,
+                    const InternalKeyComparator& /*internal_comparator*/,
-      const MutableCFOptions& /*moptions*/,
+                    const stl_wrappers::KVMap& kv_map) override {
-      const BlockBasedTableOptions& /*table_options*/,
-      const InternalKeyComparator& /*internal_comparator*/,
-      const stl_wrappers::KVMap& kv_map) override {
     delete memtable_->Unref();
     ImmutableCFOptions mem_ioptions(ioptions);
     memtable_ = new MemTable(internal_comparator_, mem_ioptions,
@@ -471,15 +465,15 @@ class MemTableConstructor: public Constructor {
     }
     return Status::OK();
   }
-  virtual InternalIterator* NewIterator(
+  InternalIterator* NewIterator(
       const SliceTransform* /*prefix_extractor*/) const override {
     return new KeyConvertingIterator(
         memtable_->NewIterator(ReadOptions(), &arena_), true);
   }
 
-  virtual bool AnywayDeleteIterator() const override { return true; }
+  bool AnywayDeleteIterator() const override { return true; }
 
-  virtual bool IsArenaMode() const override { return true; }
+  bool IsArenaMode() const override { return true; }
 
  private:
   mutable Arena arena_;
@@ -493,18 +487,16 @@ class MemTableConstructor: public Constructor {
 class InternalIteratorFromIterator : public InternalIterator {
  public:
   explicit InternalIteratorFromIterator(Iterator* it) : it_(it) {}
-  virtual bool Valid() const override { return it_->Valid(); }
+  bool Valid() const override { return it_->Valid(); }
-  virtual void Seek(const Slice& target) override { it_->Seek(target); }
+  void Seek(const Slice& target) override { it_->Seek(target); }
-  virtual void SeekForPrev(const Slice& target) override {
+  void SeekForPrev(const Slice& target) override { it_->SeekForPrev(target); }
-    it_->SeekForPrev(target);
+  void SeekToFirst() override { it_->SeekToFirst(); }
-  }
+  void SeekToLast() override { it_->SeekToLast(); }
-  virtual void SeekToFirst() override { it_->SeekToFirst(); }
+  void Next() override { it_->Next(); }
-  virtual void SeekToLast() override { it_->SeekToLast(); }
+  void Prev() override { it_->Prev(); }
-  virtual void Next() override { it_->Next(); }
-  virtual void Prev() override { it_->Prev(); }
   Slice key() const override { return it_->key(); }
   Slice value() const override { return it_->value(); }
-  virtual Status status() const override { return it_->status(); }
+  Status status() const override { return it_->status(); }
 
  private:
   std::unique_ptr<Iterator> it_;
@@ -518,15 +510,13 @@ class DBConstructor: public Constructor {
     db_ = nullptr;
     NewDB();
   }
-  ~DBConstructor() {
+  ~DBConstructor() override { delete db_; }
-    delete db_;
+  Status FinishImpl(const Options& /*options*/,
-  }
+                    const ImmutableCFOptions& /*ioptions*/,
-  virtual Status FinishImpl(
+                    const MutableCFOptions& /*moptions*/,
-      const Options& /*options*/, const ImmutableCFOptions& /*ioptions*/,
+                    const BlockBasedTableOptions& /*table_options*/,
-      const MutableCFOptions& /*moptions*/,
+                    const InternalKeyComparator& /*internal_comparator*/,
-      const BlockBasedTableOptions& /*table_options*/,
+                    const stl_wrappers::KVMap& kv_map) override {
-      const InternalKeyComparator& /*internal_comparator*/,
-      const stl_wrappers::KVMap& kv_map) override {
     delete db_;
     db_ = nullptr;
     NewDB();
@@ -538,12 +528,12 @@ class DBConstructor: public Constructor {
     return Status::OK();
   }
 
-  virtual InternalIterator* NewIterator(
+  InternalIterator* NewIterator(
       const SliceTransform* /*prefix_extractor*/) const override {
     return new InternalIteratorFromIterator(db_->NewIterator(ReadOptions()));
   }
 
-  virtual DB* db() const override { return db_; }
+  DB* db() const override { return db_; }
 
  private:
   void NewDB() {
@@ -679,9 +669,9 @@ class FixedOrLessPrefixTransform : public SliceTransform {
       prefix_len_(prefix_len) {
   }
 
-  virtual const char* Name() const override { return "rocksdb.FixedPrefix"; }
+  const char* Name() const override { return "rocksdb.FixedPrefix"; }
 
-  virtual Slice Transform(const Slice& src) const override {
+  Slice Transform(const Slice& src) const override {
     assert(InDomain(src));
     if (src.size() < prefix_len_) {
       return src;
@@ -689,14 +679,12 @@ class FixedOrLessPrefixTransform : public SliceTransform {
     return Slice(src.data(), prefix_len_);
   }
 
-  virtual bool InDomain(const Slice& /*src*/) const override { return true; }
+  bool InDomain(const Slice& /*src*/) const override { return true; }
 
-  virtual bool InRange(const Slice& dst) const override {
+  bool InRange(const Slice& dst) const override {
     return (dst.size() <= prefix_len_);
   }
-  virtual bool FullLengthEnabled(size_t* /*len*/) const override {
+  bool FullLengthEnabled(size_t* /*len*/) const override { return false; }
-    return false;
-  }
 };
 
 class HarnessTest : public testing::Test {
@@ -805,7 +793,7 @@ class HarnessTest : public testing::Test {
     moptions_ = MutableCFOptions(options_);
   }
 
-  ~HarnessTest() { delete constructor_; }
+  ~HarnessTest() override { delete constructor_; }
 
   void Add(const std::string& key, const std::string& value) {
     constructor_->Add(key, value);
@@ -2287,10 +2275,10 @@ class MockCache : public LRUCache {
             double high_pri_pool_ratio)
       : LRUCache(capacity, num_shard_bits, strict_capacity_limit,
                  high_pri_pool_ratio) {}
-  virtual Status Insert(const Slice& key, void* value, size_t charge,
+  Status Insert(const Slice& key, void* value, size_t charge,
-                        void (*deleter)(const Slice& key, void* value),
+                void (*deleter)(const Slice& key, void* value),
-                        Handle** handle = nullptr,
+                Handle** handle = nullptr,
-                        Priority priority = Priority::LOW) override {
+                Priority priority = Priority::LOW) override {
     // Replace the deleter with our own so that we keep track of data blocks
     // erased from the cache
     deleters_[key.ToString()] = deleter;
@@ -2298,8 +2286,7 @@ class MockCache : public LRUCache {
                                 priority);
   }
   // This is called by the application right after inserting a data block
-  virtual void TEST_mark_as_data_block(const Slice& key,
+  void TEST_mark_as_data_block(const Slice& key, size_t charge) override {
-                                       size_t charge) override {
     marked_data_in_cache_[key.ToString()] = charge;
     marked_size_ += charge;
   }
@@ -2487,7 +2474,7 @@ TEST_P(BlockBasedTableTest, BlockCacheLeak) {
 namespace {
 class CustomMemoryAllocator : public MemoryAllocator {
  public:
-  virtual const char* Name() const override { return "CustomMemoryAllocator"; }
+  const char* Name() const override { return "CustomMemoryAllocator"; }
 
   void* Allocate(size_t size) override {
     ++numAllocations;
@@ -3165,7 +3152,7 @@ TEST_P(IndexBlockRestartIntervalTest, IndexBlockRestartInterval) {
 class PrefixTest : public testing::Test {
  public:
   PrefixTest() : testing::Test() {}
-  ~PrefixTest() {}
+  ~PrefixTest() override {}
 };
 
 namespace {

table/two_level_iterator.cc

@@ -25,29 +25,29 @@ class TwoLevelIndexIterator : public InternalIteratorBase<BlockHandle> {
       TwoLevelIteratorState* state,
       InternalIteratorBase<BlockHandle>* first_level_iter);
 
-  virtual ~TwoLevelIndexIterator() {
+  ~TwoLevelIndexIterator() override {
     first_level_iter_.DeleteIter(false /* is_arena_mode */);
     second_level_iter_.DeleteIter(false /* is_arena_mode */);
     delete state_;
   }
 
-  virtual void Seek(const Slice& target) override;
+  void Seek(const Slice& target) override;
-  virtual void SeekForPrev(const Slice& target) override;
+  void SeekForPrev(const Slice& target) override;
-  virtual void SeekToFirst() override;
+  void SeekToFirst() override;
-  virtual void SeekToLast() override;
+  void SeekToLast() override;
-  virtual void Next() override;
+  void Next() override;
-  virtual void Prev() override;
+  void Prev() override;
 
-  virtual bool Valid() const override { return second_level_iter_.Valid(); }
+  bool Valid() const override { return second_level_iter_.Valid(); }
-  virtual Slice key() const override {
+  Slice key() const override {
     assert(Valid());
     return second_level_iter_.key();
   }
-  virtual BlockHandle value() const override {
+  BlockHandle value() const override {
     assert(Valid());
     return second_level_iter_.value();
   }
-  virtual Status status() const override {
+  Status status() const override {
     if (!first_level_iter_.status().ok()) {
       assert(second_level_iter_.iter() == nullptr);
       return first_level_iter_.status();
@@ -58,10 +58,10 @@ class TwoLevelIndexIterator : public InternalIteratorBase<BlockHandle> {
       return status_;
     }
   }
-  virtual void SetPinnedItersMgr(
+  void SetPinnedItersMgr(
       PinnedIteratorsManager* /*pinned_iters_mgr*/) override {}
-  virtual bool IsKeyPinned() const override { return false; }
+  bool IsKeyPinned() const override { return false; }
-  virtual bool IsValuePinned() const override { return false; }
+  bool IsValuePinned() const override { return false; }
 
  private:
   void SaveError(const Status& s) {

tools/db_bench_tool.cc

@@ -1205,7 +1205,7 @@ class ReportFileOpEnv : public EnvWrapper {
                    ReportFileOpCounters* counters)
           : target_(std::move(target)), counters_(counters) {}
 
-      virtual Status Read(size_t n, Slice* result, char* scratch) override {
+      Status Read(size_t n, Slice* result, char* scratch) override {
         counters_->read_counter_.fetch_add(1, std::memory_order_relaxed);
         Status rv = target_->Read(n, result, scratch);
         counters_->bytes_read_.fetch_add(result->size(),
@@ -1213,7 +1213,7 @@ class ReportFileOpEnv : public EnvWrapper {
         return rv;
       }
 
-      virtual Status Skip(uint64_t n) override { return target_->Skip(n); }
+      Status Skip(uint64_t n) override { return target_->Skip(n); }
     };
 
     Status s = target()->NewSequentialFile(f, r, soptions);
@@ -1236,8 +1236,8 @@ class ReportFileOpEnv : public EnvWrapper {
       CountingFile(unique_ptr<RandomAccessFile>&& target,
                    ReportFileOpCounters* counters)
           : target_(std::move(target)), counters_(counters) {}
-      virtual Status Read(uint64_t offset, size_t n, Slice* result,
+      Status Read(uint64_t offset, size_t n, Slice* result,
-                          char* scratch) const override {
+                  char* scratch) const override {
         counters_->read_counter_.fetch_add(1, std::memory_order_relaxed);
         Status rv = target_->Read(offset, n, result, scratch);
         counters_->bytes_read_.fetch_add(result->size(),
@@ -2050,16 +2050,17 @@ class Benchmark {
           no_auto_recovery_(false),
           recovery_complete_(false) {}
 
-    ~ErrorHandlerListener() {}
+    ~ErrorHandlerListener() override {}
 
     void OnErrorRecoveryBegin(BackgroundErrorReason /*reason*/,
-                              Status /*bg_error*/, bool* auto_recovery) {
+                              Status /*bg_error*/,
+                              bool* auto_recovery) override {
       if (*auto_recovery && no_auto_recovery_) {
         *auto_recovery = false;
       }
     }
 
-    void OnErrorRecoveryCompleted(Status /*old_bg_error*/) {
+    void OnErrorRecoveryCompleted(Status /*old_bg_error*/) override {
       InstrumentedMutexLock l(&mutex_);
       recovery_complete_ = true;
       cv_.SignalAll();
@@ -2310,13 +2311,13 @@ class Benchmark {
 
   class KeepFilter : public CompactionFilter {
    public:
-    virtual bool Filter(int /*level*/, const Slice& /*key*/,
+    bool Filter(int /*level*/, const Slice& /*key*/, const Slice& /*value*/,
-                        const Slice& /*value*/, std::string* /*new_value*/,
+                std::string* /*new_value*/,
-                        bool* /*value_changed*/) const override {
+                bool* /*value_changed*/) const override {
       return false;
     }
 
-    virtual const char* Name() const override { return "KeepFilter"; }
+    const char* Name() const override { return "KeepFilter"; }
   };
 
   std::shared_ptr<Cache> NewCache(int64_t capacity) {

tools/ldb_cmd.cc

@@ -1869,7 +1869,7 @@ void ChangeCompactionStyleCommand::DoCommand() {
 namespace {
 
 struct StdErrReporter : public log::Reader::Reporter {
-  virtual void Corruption(size_t /*bytes*/, const Status& s) override {
+  void Corruption(size_t /*bytes*/, const Status& s) override {
     std::cerr << "Corruption detected in log file " << s.ToString() << "\n";
   }
 };
@@ -1894,74 +1894,71 @@ class InMemoryHandler : public WriteBatch::Handler {
     }
   }
 
-  virtual Status PutCF(uint32_t cf, const Slice& key,
+  Status PutCF(uint32_t cf, const Slice& key, const Slice& value) override {
-                       const Slice& value) override {
     row_ << "PUT(" << cf << ") : ";
     commonPutMerge(key, value);
     return Status::OK();
   }
 
-  virtual Status MergeCF(uint32_t cf, const Slice& key,
+  Status MergeCF(uint32_t cf, const Slice& key, const Slice& value) override {
-                         const Slice& value) override {
     row_ << "MERGE(" << cf << ") : ";
     commonPutMerge(key, value);
     return Status::OK();
   }
 
-  virtual Status MarkNoop(bool)
+  Status MarkNoop(bool) override {
-                          override {
     row_ << "NOOP ";
     return Status::OK();
   }
 
-  virtual Status DeleteCF(uint32_t cf, const Slice& key) override {
+  Status DeleteCF(uint32_t cf, const Slice& key) override {
     row_ << "DELETE(" << cf << ") : ";
     row_ << LDBCommand::StringToHex(key.ToString()) << " ";
     return Status::OK();
   }
 
-  virtual Status SingleDeleteCF(uint32_t cf, const Slice& key) override {
+  Status SingleDeleteCF(uint32_t cf, const Slice& key) override {
     row_ << "SINGLE_DELETE(" << cf << ") : ";
     row_ << LDBCommand::StringToHex(key.ToString()) << " ";
     return Status::OK();
   }
 
-  virtual Status DeleteRangeCF(uint32_t cf, const Slice& begin_key,
+  Status DeleteRangeCF(uint32_t cf, const Slice& begin_key,
-                               const Slice& end_key) override {
+                       const Slice& end_key) override {
     row_ << "DELETE_RANGE(" << cf << ") : ";
     row_ << LDBCommand::StringToHex(begin_key.ToString()) << " ";
     row_ << LDBCommand::StringToHex(end_key.ToString()) << " ";
     return Status::OK();
   }
 
-  virtual Status MarkBeginPrepare(bool unprepare) override {
+  Status MarkBeginPrepare(bool unprepare) override {
     row_ << "BEGIN_PREPARE(";
     row_ << (unprepare ? "true" : "false") << ") ";
     return Status::OK();
   }
 
-  virtual Status MarkEndPrepare(const Slice& xid) override {
+  Status MarkEndPrepare(const Slice& xid) override {
     row_ << "END_PREPARE(";
     row_ << LDBCommand::StringToHex(xid.ToString()) << ") ";
     return Status::OK();
   }
 
-  virtual Status MarkRollback(const Slice& xid) override {
+  Status MarkRollback(const Slice& xid) override {
     row_ << "ROLLBACK(";
     row_ << LDBCommand::StringToHex(xid.ToString()) << ") ";
     return Status::OK();
   }
 
-  virtual Status MarkCommit(const Slice& xid) override {
+  Status MarkCommit(const Slice& xid) override {
     row_ << "COMMIT(";
     row_ << LDBCommand::StringToHex(xid.ToString()) << ") ";
     return Status::OK();
   }
 
-  virtual ~InMemoryHandler() {}
+  ~InMemoryHandler() override {}
 
  protected:
-  virtual bool WriteAfterCommit() const override { return write_after_commit_; }
+  bool WriteAfterCommit() const override { return write_after_commit_; }
 
  private:
   std::stringstream& row_;

tools/sst_dump_test.cc

@@ -89,7 +89,7 @@ class SSTDumpToolTest : public testing::Test {
  public:
   SSTDumpToolTest() { testDir_ = test::TmpDir(); }
 
-  ~SSTDumpToolTest() {}
+  ~SSTDumpToolTest() override {}
 
   std::string MakeFilePath(const std::string& file_name) const {
     std::string path(testDir_);

tools/trace_analyzer_test.cc

@@ -50,7 +50,7 @@ class TraceAnalyzerTest : public testing::Test {
     dbname_ = test_path_ + "/db";
   }
 
-  ~TraceAnalyzerTest() {}
+  ~TraceAnalyzerTest() override {}
 
   void GenerateTrace(std::string trace_path) {
     Options options;

util/auto_roll_logger_test.cc

@@ -28,13 +28,13 @@ namespace {
 class NoSleepEnv : public EnvWrapper {
  public:
   NoSleepEnv(Env* base) : EnvWrapper(base) {}
-  virtual void SleepForMicroseconds(int micros) override {
+  void SleepForMicroseconds(int micros) override {
     fake_time_ += static_cast<uint64_t>(micros);
   }
 
-  virtual uint64_t NowNanos() override { return fake_time_ * 1000; }
+  uint64_t NowNanos() override { return fake_time_ * 1000; }
 
-  virtual uint64_t NowMicros() override { return fake_time_; }
+  uint64_t NowMicros() override { return fake_time_; }
 
  private:
   uint64_t fake_time_ = 6666666666;

util/bloom.cc

@@ -172,9 +172,9 @@ class FullFilterBitsReader : public FilterBitsReader {
     }
   }
 
-  ~FullFilterBitsReader() {}
+  ~FullFilterBitsReader() override {}
 
-  virtual bool MayMatch(const Slice& entry) override {
+  bool MayMatch(const Slice& entry) override {
     if (data_len_ <= 5) {   // remain same with original filter
       return false;
     }
@@ -274,15 +274,11 @@ class BloomFilterPolicy : public FilterPolicy {
     initialize();
   }
 
-  ~BloomFilterPolicy() {
+  ~BloomFilterPolicy() override {}
-  }
 
-  virtual const char* Name() const override {
+  const char* Name() const override { return "rocksdb.BuiltinBloomFilter"; }
-    return "rocksdb.BuiltinBloomFilter";
-  }
 
-  virtual void CreateFilter(const Slice* keys, int n,
+  void CreateFilter(const Slice* keys, int n, std::string* dst) const override {
-                            std::string* dst) const override {
     // Compute bloom filter size (in both bits and bytes)
     size_t bits = n * bits_per_key_;
 
@@ -310,8 +306,7 @@ class BloomFilterPolicy : public FilterPolicy {
     }
   }
 
-  virtual bool KeyMayMatch(const Slice& key,
+  bool KeyMayMatch(const Slice& key, const Slice& bloom_filter) const override {
-                           const Slice& bloom_filter) const override {
     const size_t len = bloom_filter.size();
     if (len < 2) return false;
 
@@ -337,7 +332,7 @@ class BloomFilterPolicy : public FilterPolicy {
     return true;
   }
 
-  virtual FilterBitsBuilder* GetFilterBitsBuilder() const override {
+  FilterBitsBuilder* GetFilterBitsBuilder() const override {
     if (use_block_based_builder_) {
       return nullptr;
     }
@@ -345,8 +340,7 @@ class BloomFilterPolicy : public FilterPolicy {
     return new FullFilterBitsBuilder(bits_per_key_, num_probes_);
   }
 
-  virtual FilterBitsReader* GetFilterBitsReader(const Slice& contents)
+  FilterBitsReader* GetFilterBitsReader(const Slice& contents) const override {
-      const override {
     return new FullFilterBitsReader(contents);
   }
 

util/bloom_test.cc

@@ -63,9 +63,7 @@ class BloomTest : public testing::Test {
   BloomTest() : policy_(
       NewBloomFilterPolicy(FLAGS_bits_per_key)) {}
 
-  ~BloomTest() {
+  ~BloomTest() override { delete policy_; }
-    delete policy_;
-  }
 
   void Reset() {
     keys_.clear();
@@ -192,9 +190,7 @@ class FullBloomTest : public testing::Test {
     Reset();
   }
 
-  ~FullBloomTest() {
+  ~FullBloomTest() override { delete policy_; }
-    delete policy_;
-  }
 
   FullFilterBitsBuilder* GetFullFilterBitsBuilder() {
     return dynamic_cast<FullFilterBitsBuilder*>(bits_builder_.get());

util/comparator.cc

@@ -22,20 +22,16 @@ class BytewiseComparatorImpl : public Comparator {
  public:
   BytewiseComparatorImpl() { }
 
-  virtual const char* Name() const override {
+  const char* Name() const override { return "leveldb.BytewiseComparator"; }
-    return "leveldb.BytewiseComparator";
-  }
 
-  virtual int Compare(const Slice& a, const Slice& b) const override {
+  int Compare(const Slice& a, const Slice& b) const override {
     return a.compare(b);
   }
 
-  virtual bool Equal(const Slice& a, const Slice& b) const override {
+  bool Equal(const Slice& a, const Slice& b) const override { return a == b; }
-    return a == b;
-  }
 
-  virtual void FindShortestSeparator(std::string* start,
+  void FindShortestSeparator(std::string* start,
-                                     const Slice& limit) const override {
+                             const Slice& limit) const override {
     // Find length of common prefix
     size_t min_length = std::min(start->size(), limit.size());
     size_t diff_index = 0;
@@ -85,7 +81,7 @@ class BytewiseComparatorImpl : public Comparator {
     }
   }
 
-  virtual void FindShortSuccessor(std::string* key) const override {
+  void FindShortSuccessor(std::string* key) const override {
     // Find first character that can be incremented
     size_t n = key->size();
     for (size_t i = 0; i < n; i++) {
@@ -99,8 +95,8 @@ class BytewiseComparatorImpl : public Comparator {
     // *key is a run of 0xffs.  Leave it alone.
   }
 
-  virtual bool IsSameLengthImmediateSuccessor(const Slice& s,
+  bool IsSameLengthImmediateSuccessor(const Slice& s,
-                                              const Slice& t) const override {
+                                      const Slice& t) const override {
     if (s.size() != t.size() || s.size() == 0) {
       return false;
     }
@@ -125,7 +121,7 @@ class BytewiseComparatorImpl : public Comparator {
     }
   }
 
-  virtual bool CanKeysWithDifferentByteContentsBeEqual() const override {
+  bool CanKeysWithDifferentByteContentsBeEqual() const override {
     return false;
   }
 };
@@ -134,11 +130,11 @@ class ReverseBytewiseComparatorImpl : public BytewiseComparatorImpl {
  public:
   ReverseBytewiseComparatorImpl() { }
 
-  virtual const char* Name() const override {
+  const char* Name() const override {
     return "rocksdb.ReverseBytewiseComparator";
   }
 
-  virtual int Compare(const Slice& a, const Slice& b) const override {
+  int Compare(const Slice& a, const Slice& b) const override {
     return -a.compare(b);
   }
 
@@ -193,7 +189,7 @@ class ReverseBytewiseComparatorImpl : public BytewiseComparatorImpl {
     // Don't do anything for simplicity.
   }
 
-  virtual bool CanKeysWithDifferentByteContentsBeEqual() const override {
+  bool CanKeysWithDifferentByteContentsBeEqual() const override {
     return false;
   }
 };

util/delete_scheduler_test.cc

@@ -38,7 +38,7 @@ class DeleteSchedulerTest : public testing::Test {
     }
   }
 
-  ~DeleteSchedulerTest() {
+  ~DeleteSchedulerTest() override {
     rocksdb::SyncPoint::GetInstance()->DisableProcessing();
     rocksdb::SyncPoint::GetInstance()->LoadDependency({});
     rocksdb::SyncPoint::GetInstance()->ClearAllCallBacks();

util/event_logger_test.cc

@@ -15,7 +15,7 @@ class EventLoggerTest : public testing::Test {};
 class StringLogger : public Logger {
  public:
   using Logger::Logv;
-  virtual void Logv(const char* format, va_list ap) override {
+  void Logv(const char* format, va_list ap) override {
     vsnprintf(buffer_, sizeof(buffer_), format, ap);
   }
   char* buffer() { return buffer_; }

util/file_reader_writer.cc

@@ -595,96 +595,93 @@ class ReadaheadRandomAccessFile : public RandomAccessFile {
 
  ReadaheadRandomAccessFile& operator=(const ReadaheadRandomAccessFile&) = delete;
 
-  virtual Status Read(uint64_t offset, size_t n, Slice* result,
+ Status Read(uint64_t offset, size_t n, Slice* result,
-                      char* scratch) const override {
+             char* scratch) const override {
-
+   if (n + alignment_ >= readahead_size_) {
-    if (n + alignment_ >= readahead_size_) {
+     return file_->Read(offset, n, result, scratch);
-      return file_->Read(offset, n, result, scratch);
+   }
-    }
+
-
+   std::unique_lock<std::mutex> lk(lock_);
-    std::unique_lock<std::mutex> lk(lock_);
+
-
+   size_t cached_len = 0;
-    size_t cached_len = 0;
+   // Check if there is a cache hit, means that [offset, offset + n) is either
-    // Check if there is a cache hit, means that [offset, offset + n) is either
+   // completely or partially in the buffer
-    // completely or partially in the buffer
+   // If it's completely cached, including end of file case when offset + n is
-    // If it's completely cached, including end of file case when offset + n is
+   // greater than EOF, return
-    // greater than EOF, return
+   if (TryReadFromCache(offset, n, &cached_len, scratch) &&
-    if (TryReadFromCache(offset, n, &cached_len, scratch) &&
+       (cached_len == n ||
-        (cached_len == n ||
+        // End of file
-         // End of file
+        buffer_.CurrentSize() < readahead_size_)) {
-         buffer_.CurrentSize() < readahead_size_)) {
+     *result = Slice(scratch, cached_len);
-      *result = Slice(scratch, cached_len);
+     return Status::OK();
-      return Status::OK();
+   }
-    }
+   size_t advanced_offset = static_cast<size_t>(offset + cached_len);
-    size_t advanced_offset = static_cast<size_t>(offset + cached_len);
+   // In the case of cache hit advanced_offset is already aligned, means that
-    // In the case of cache hit advanced_offset is already aligned, means that
+   // chunk_offset equals to advanced_offset
-    // chunk_offset equals to advanced_offset
+   size_t chunk_offset = TruncateToPageBoundary(alignment_, advanced_offset);
-    size_t chunk_offset = TruncateToPageBoundary(alignment_, advanced_offset);
+   Slice readahead_result;
-    Slice readahead_result;
+
-
+   Status s = ReadIntoBuffer(chunk_offset, readahead_size_);
-    Status s = ReadIntoBuffer(chunk_offset, readahead_size_);
+   if (s.ok()) {
-    if (s.ok()) {
+     // In the case of cache miss, i.e. when cached_len equals 0, an offset can
-      // In the case of cache miss, i.e. when cached_len equals 0, an offset can
+     // exceed the file end position, so the following check is required
-      // exceed the file end position, so the following check is required
+     if (advanced_offset < chunk_offset + buffer_.CurrentSize()) {
-      if (advanced_offset < chunk_offset + buffer_.CurrentSize()) {
+       // In the case of cache miss, the first chunk_padding bytes in buffer_
-        // In the case of cache miss, the first chunk_padding bytes in buffer_
+       // are
-        // are
+       // stored for alignment only and must be skipped
-        // stored for alignment only and must be skipped
+       size_t chunk_padding = advanced_offset - chunk_offset;
-        size_t chunk_padding = advanced_offset - chunk_offset;
+       auto remaining_len =
-        auto remaining_len =
+           std::min(buffer_.CurrentSize() - chunk_padding, n - cached_len);
-            std::min(buffer_.CurrentSize() - chunk_padding, n - cached_len);
+       memcpy(scratch + cached_len, buffer_.BufferStart() + chunk_padding,
-        memcpy(scratch + cached_len, buffer_.BufferStart() + chunk_padding,
+              remaining_len);
-               remaining_len);
+       *result = Slice(scratch, cached_len + remaining_len);
-        *result = Slice(scratch, cached_len + remaining_len);
+     } else {
-      } else {
+       *result = Slice(scratch, cached_len);
-        *result = Slice(scratch, cached_len);
+     }
-      }
+   }
-    }
+   return s;
-    return s;
+ }
-  }
+
-
+ Status Prefetch(uint64_t offset, size_t n) override {
-  virtual Status Prefetch(uint64_t offset, size_t n) override {
+   if (n < readahead_size_) {
-    if (n < readahead_size_) {
+     // Don't allow smaller prefetches than the configured `readahead_size_`.
-      // Don't allow smaller prefetches than the configured `readahead_size_`.
+     // `Read()` assumes a smaller prefetch buffer indicates EOF was reached.
-      // `Read()` assumes a smaller prefetch buffer indicates EOF was reached.
+     return Status::OK();
-      return Status::OK();
+   }
-    }
+   size_t offset_ = static_cast<size_t>(offset);
-    size_t offset_ = static_cast<size_t>(offset);
+   size_t prefetch_offset = TruncateToPageBoundary(alignment_, offset_);
-    size_t prefetch_offset = TruncateToPageBoundary(alignment_, offset_);
+   if (prefetch_offset == buffer_offset_) {
-    if (prefetch_offset == buffer_offset_) {
+     return Status::OK();
-      return Status::OK();
+   }
-    }
+   return ReadIntoBuffer(prefetch_offset,
-    return ReadIntoBuffer(prefetch_offset,
+                         Roundup(offset_ + n, alignment_) - prefetch_offset);
-                          Roundup(offset_ + n, alignment_) - prefetch_offset);
+ }
-  }
+
-
+ size_t GetUniqueId(char* id, size_t max_size) const override {
-  virtual size_t GetUniqueId(char* id, size_t max_size) const override {
+   return file_->GetUniqueId(id, max_size);
-    return file_->GetUniqueId(id, max_size);
+ }
-  }
+
-
+ void Hint(AccessPattern pattern) override { file_->Hint(pattern); }
-  virtual void Hint(AccessPattern pattern) override { file_->Hint(pattern); }
+
-
+ Status InvalidateCache(size_t offset, size_t length) override {
-  virtual Status InvalidateCache(size_t offset, size_t length) override {
+   return file_->InvalidateCache(offset, length);
-    return file_->InvalidateCache(offset, length);
+ }
-  }
+
-
+ bool use_direct_io() const override { return file_->use_direct_io(); }
-  virtual bool use_direct_io() const override {
+
-    return file_->use_direct_io();
+private:
-  }
+ bool TryReadFromCache(uint64_t offset, size_t n, size_t* cached_len,
-
+                       char* scratch) const {
- private:
+   if (offset < buffer_offset_ ||
-  bool TryReadFromCache(uint64_t offset, size_t n, size_t* cached_len,
+       offset >= buffer_offset_ + buffer_.CurrentSize()) {
-                         char* scratch) const {
+     *cached_len = 0;
-    if (offset < buffer_offset_ ||
+     return false;
-        offset >= buffer_offset_ + buffer_.CurrentSize()) {
+   }
-      *cached_len = 0;
+   uint64_t offset_in_buffer = offset - buffer_offset_;
-      return false;
+   *cached_len = std::min(
-    }
+       buffer_.CurrentSize() - static_cast<size_t>(offset_in_buffer), n);
-    uint64_t offset_in_buffer = offset - buffer_offset_;
+   memcpy(scratch, buffer_.BufferStart() + offset_in_buffer, *cached_len);
-    *cached_len = std::min(
+   return true;
-        buffer_.CurrentSize() - static_cast<size_t>(offset_in_buffer), n);
-    memcpy(scratch, buffer_.BufferStart() + offset_in_buffer, *cached_len);
-    return true;
   }
 
   Status ReadIntoBuffer(uint64_t offset, size_t n) const {

util/file_reader_writer_test.cc

@@ -20,13 +20,13 @@ TEST_F(WritableFileWriterTest, RangeSync) {
   class FakeWF : public WritableFile {
    public:
     explicit FakeWF() : size_(0), last_synced_(0) {}
-    ~FakeWF() {}
+    ~FakeWF() override {}
 
     Status Append(const Slice& data) override {
       size_ += data.size();
       return Status::OK();
     }
-    virtual Status Truncate(uint64_t /*size*/) override { return Status::OK(); }
+    Status Truncate(uint64_t /*size*/) override { return Status::OK(); }
     Status Close() override {
       EXPECT_GE(size_, last_synced_ + kMb);
       EXPECT_LT(size_, last_synced_ + 2 * kMb);
@@ -97,7 +97,7 @@ TEST_F(WritableFileWriterTest, IncrementalBuffer) {
         : file_data_(_file_data),
           use_direct_io_(_use_direct_io),
           no_flush_(_no_flush) {}
-    ~FakeWF() {}
+    ~FakeWF() override {}
 
     Status Append(const Slice& data) override {
       file_data_->append(data.data(), data.size());
@@ -113,7 +113,7 @@ TEST_F(WritableFileWriterTest, IncrementalBuffer) {
       return Status::OK();
     }
 
-    virtual Status Truncate(uint64_t size) override {
+    Status Truncate(uint64_t size) override {
       file_data_->resize(size);
       return Status::OK();
     }
@@ -183,7 +183,7 @@ TEST_F(WritableFileWriterTest, AppendStatusReturn) {
    public:
     explicit FakeWF() : use_direct_io_(false), io_error_(false) {}
 
-    virtual bool use_direct_io() const override { return use_direct_io_; }
+    bool use_direct_io() const override { return use_direct_io_; }
     Status Append(const Slice& /*data*/) override {
       if (io_error_) {
         return Status::IOError("Fake IO error");
@@ -226,7 +226,7 @@ class ReadaheadRandomAccessFileTest
   static std::vector<size_t> GetReadaheadSizeList() {
     return {1lu << 12, 1lu << 16};
   }
-  virtual void SetUp() override {
+  void SetUp() override {
     readahead_size_ = GetParam();
     scratch_.reset(new char[2 * readahead_size_]);
     ResetSourceStr();

util/filelock_test.cc

@@ -25,8 +25,7 @@ class LockTest : public testing::Test {
     current_ = this;
   }
 
-  ~LockTest() {
+  ~LockTest() override {}
-  }
 
   Status LockFile(FileLock** db_lock) {
     return env_->LockFile(file_, db_lock);

util/slice.cc

@@ -32,27 +32,27 @@ class FixedPrefixTransform : public SliceTransform {
         // the class implementation itself.
         name_("rocksdb.FixedPrefix." + ToString(prefix_len_)) {}
 
-  virtual const char* Name() const override { return name_.c_str(); }
+  const char* Name() const override { return name_.c_str(); }
 
-  virtual Slice Transform(const Slice& src) const override {
+  Slice Transform(const Slice& src) const override {
     assert(InDomain(src));
     return Slice(src.data(), prefix_len_);
   }
 
-  virtual bool InDomain(const Slice& src) const override {
+  bool InDomain(const Slice& src) const override {
     return (src.size() >= prefix_len_);
   }
 
-  virtual bool InRange(const Slice& dst) const override {
+  bool InRange(const Slice& dst) const override {
     return (dst.size() == prefix_len_);
   }
 
-  virtual bool FullLengthEnabled(size_t* len) const override {
+  bool FullLengthEnabled(size_t* len) const override {
     *len = prefix_len_;
     return true;
   }
 
-  virtual bool SameResultWhenAppended(const Slice& prefix) const override {
+  bool SameResultWhenAppended(const Slice& prefix) const override {
     return InDomain(prefix);
   }
 };
@@ -72,25 +72,25 @@ class CappedPrefixTransform : public SliceTransform {
         // the class implementation itself.
         name_("rocksdb.CappedPrefix." + ToString(cap_len_)) {}
 
-  virtual const char* Name() const override { return name_.c_str(); }
+  const char* Name() const override { return name_.c_str(); }
 
-  virtual Slice Transform(const Slice& src) const override {
+  Slice Transform(const Slice& src) const override {
     assert(InDomain(src));
     return Slice(src.data(), std::min(cap_len_, src.size()));
   }
 
-  virtual bool InDomain(const Slice& /*src*/) const override { return true; }
+  bool InDomain(const Slice& /*src*/) const override { return true; }
 
-  virtual bool InRange(const Slice& dst) const override {
+  bool InRange(const Slice& dst) const override {
     return (dst.size() <= cap_len_);
   }
 
-  virtual bool FullLengthEnabled(size_t* len) const override {
+  bool FullLengthEnabled(size_t* len) const override {
     *len = cap_len_;
     return true;
   }
 
-  virtual bool SameResultWhenAppended(const Slice& prefix) const override {
+  bool SameResultWhenAppended(const Slice& prefix) const override {
     return prefix.size() >= cap_len_;
   }
 };
@@ -99,15 +99,15 @@ class NoopTransform : public SliceTransform {
  public:
   explicit NoopTransform() { }
 
-  virtual const char* Name() const override { return "rocksdb.Noop"; }
+  const char* Name() const override { return "rocksdb.Noop"; }
 
-  virtual Slice Transform(const Slice& src) const override { return src; }
+  Slice Transform(const Slice& src) const override { return src; }
 
-  virtual bool InDomain(const Slice& /*src*/) const override { return true; }
+  bool InDomain(const Slice& /*src*/) const override { return true; }
 
-  virtual bool InRange(const Slice& /*dst*/) const override { return true; }
+  bool InRange(const Slice& /*dst*/) const override { return true; }
 
-  virtual bool SameResultWhenAppended(const Slice& /*prefix*/) const override {
+  bool SameResultWhenAppended(const Slice& /*prefix*/) const override {
     return false;
   }
 };

util/slice_transform_test.cc

@@ -57,7 +57,7 @@ class SliceTransformDBTest : public testing::Test {
     EXPECT_OK(DestroyDB(dbname_, last_options_));
   }
 
-  ~SliceTransformDBTest() {
+  ~SliceTransformDBTest() override {
     delete db_;
     EXPECT_OK(DestroyDB(dbname_, last_options_));
   }

util/testutil.cc

@@ -87,11 +87,9 @@ class Uint64ComparatorImpl : public Comparator {
  public:
   Uint64ComparatorImpl() {}
 
-  virtual const char* Name() const override {
+  const char* Name() const override { return "rocksdb.Uint64Comparator"; }
-    return "rocksdb.Uint64Comparator";
-  }
 
-  virtual int Compare(const Slice& a, const Slice& b) const override {
+  int Compare(const Slice& a, const Slice& b) const override {
     assert(a.size() == sizeof(uint64_t) && b.size() == sizeof(uint64_t));
     const uint64_t* left = reinterpret_cast<const uint64_t*>(a.data());
     const uint64_t* right = reinterpret_cast<const uint64_t*>(b.data());
@@ -108,14 +106,12 @@ class Uint64ComparatorImpl : public Comparator {
     }
   }
 
-  virtual void FindShortestSeparator(std::string* /*start*/,
+  void FindShortestSeparator(std::string* /*start*/,
-                                     const Slice& /*limit*/) const override {
+                             const Slice& /*limit*/) const override {
     return;
   }
 
-  virtual void FindShortSuccessor(std::string* /*key*/) const override {
+  void FindShortSuccessor(std::string* /*key*/) const override { return; }
-    return;
-  }
 };
 }  // namespace
 

utilities/backupable/backupable_db.cc

@@ -92,7 +92,7 @@ class BackupEngineImpl : public BackupEngine {
  public:
   BackupEngineImpl(Env* db_env, const BackupableDBOptions& options,
                    bool read_only = false);
-  ~BackupEngineImpl();
+  ~BackupEngineImpl() override;
   Status CreateNewBackupWithMetadata(DB* db, const std::string& app_metadata,
                                      bool flush_before_backup = false,
                                      std::function<void()> progress_callback =
@@ -118,7 +118,7 @@ class BackupEngineImpl : public BackupEngine {
                                restore_options);
   }
 
-  virtual Status VerifyBackup(BackupID backup_id) override;
+  Status VerifyBackup(BackupID backup_id) override;
 
   Status Initialize();
 
@@ -1853,34 +1853,33 @@ class BackupEngineReadOnlyImpl : public BackupEngineReadOnly {
   BackupEngineReadOnlyImpl(Env* db_env, const BackupableDBOptions& options)
       : backup_engine_(new BackupEngineImpl(db_env, options, true)) {}
 
-  virtual ~BackupEngineReadOnlyImpl() {}
+  ~BackupEngineReadOnlyImpl() override {}
 
   // The returned BackupInfos are in chronological order, which means the
   // latest backup comes last.
-  virtual void GetBackupInfo(std::vector<BackupInfo>* backup_info) override {
+  void GetBackupInfo(std::vector<BackupInfo>* backup_info) override {
     backup_engine_->GetBackupInfo(backup_info);
   }
 
-  virtual void GetCorruptedBackups(
+  void GetCorruptedBackups(std::vector<BackupID>* corrupt_backup_ids) override {
-      std::vector<BackupID>* corrupt_backup_ids) override {
     backup_engine_->GetCorruptedBackups(corrupt_backup_ids);
   }
 
-  virtual Status RestoreDBFromBackup(
+  Status RestoreDBFromBackup(
       BackupID backup_id, const std::string& db_dir, const std::string& wal_dir,
       const RestoreOptions& restore_options = RestoreOptions()) override {
     return backup_engine_->RestoreDBFromBackup(backup_id, db_dir, wal_dir,
                                                restore_options);
   }
 
-  virtual Status RestoreDBFromLatestBackup(
+  Status RestoreDBFromLatestBackup(
       const std::string& db_dir, const std::string& wal_dir,
       const RestoreOptions& restore_options = RestoreOptions()) override {
     return backup_engine_->RestoreDBFromLatestBackup(db_dir, wal_dir,
                                                      restore_options);
   }
 
-  virtual Status VerifyBackup(BackupID backup_id) override {
+  Status VerifyBackup(BackupID backup_id) override {
     return backup_engine_->VerifyBackup(backup_id);
   }
 

utilities/backupable/backupable_db_test.cc

@@ -44,51 +44,42 @@ class DummyDB : public StackableDB {
      : StackableDB(nullptr), options_(options), dbname_(dbname),
        deletions_enabled_(true), sequence_number_(0) {}
 
-  virtual SequenceNumber GetLatestSequenceNumber() const override {
+  SequenceNumber GetLatestSequenceNumber() const override {
     return ++sequence_number_;
   }
 
-  virtual const std::string& GetName() const override {
+  const std::string& GetName() const override { return dbname_; }
-    return dbname_;
-  }
 
-  virtual Env* GetEnv() const override {
+  Env* GetEnv() const override { return options_.env; }
-    return options_.env;
-  }
 
   using DB::GetOptions;
-  virtual Options GetOptions(
+  Options GetOptions(ColumnFamilyHandle* /*column_family*/) const override {
-      ColumnFamilyHandle* /*column_family*/) const override {
     return options_;
   }
 
-  virtual DBOptions GetDBOptions() const override {
+  DBOptions GetDBOptions() const override { return DBOptions(options_); }
-    return DBOptions(options_);
-  }
 
-  virtual Status EnableFileDeletions(bool /*force*/) override {
+  Status EnableFileDeletions(bool /*force*/) override {
     EXPECT_TRUE(!deletions_enabled_);
     deletions_enabled_ = true;
     return Status::OK();
   }
 
-  virtual Status DisableFileDeletions() override {
+  Status DisableFileDeletions() override {
     EXPECT_TRUE(deletions_enabled_);
     deletions_enabled_ = false;
     return Status::OK();
   }
 
-  virtual Status GetLiveFiles(std::vector<std::string>& vec, uint64_t* mfs,
+  Status GetLiveFiles(std::vector<std::string>& vec, uint64_t* mfs,
-                              bool /*flush_memtable*/ = true) override {
+                      bool /*flush_memtable*/ = true) override {
     EXPECT_TRUE(!deletions_enabled_);
     vec = live_files_;
     *mfs = 100;
     return Status::OK();
   }
 
-  virtual ColumnFamilyHandle* DefaultColumnFamily() const override {
+  ColumnFamilyHandle* DefaultColumnFamily() const override { return nullptr; }
-    return nullptr;
-  }
 
   class DummyLogFile : public LogFile {
    public:
@@ -96,36 +87,32 @@ class DummyDB : public StackableDB {
      DummyLogFile(const std::string& path, bool alive = true)
          : path_(path), alive_(alive) {}
 
-    virtual std::string PathName() const override {
+     std::string PathName() const override { return path_; }
-      return path_;
-    }
 
-    virtual uint64_t LogNumber() const override {
+     uint64_t LogNumber() const override {
-      // what business do you have calling this method?
+       // what business do you have calling this method?
-      ADD_FAILURE();
+       ADD_FAILURE();
-      return 0;
+       return 0;
-    }
+     }
 
-    virtual WalFileType Type() const override {
+     WalFileType Type() const override {
-      return alive_ ? kAliveLogFile : kArchivedLogFile;
+       return alive_ ? kAliveLogFile : kArchivedLogFile;
-    }
+     }
 
-    virtual SequenceNumber StartSequence() const override {
+     SequenceNumber StartSequence() const override {
-      // this seqnum guarantees the dummy file will be included in the backup
+       // this seqnum guarantees the dummy file will be included in the backup
-      // as long as it is alive.
+       // as long as it is alive.
-      return kMaxSequenceNumber;
+       return kMaxSequenceNumber;
-    }
+     }
 
-    virtual uint64_t SizeFileBytes() const override {
+     uint64_t SizeFileBytes() const override { return 0; }
-      return 0;
-    }
 
-   private:
+    private:
-    std::string path_;
+     std::string path_;
-    bool alive_;
+     bool alive_;
   }; // DummyLogFile
 
-  virtual Status GetSortedWalFiles(VectorLogPtr& files) override {
+  Status GetSortedWalFiles(VectorLogPtr& files) override {
     EXPECT_TRUE(!deletions_enabled_);
     files.resize(wal_files_.size());
     for (size_t i = 0; i < files.size(); ++i) {
@@ -136,7 +123,7 @@ class DummyDB : public StackableDB {
   }
 
   // To avoid FlushWAL called on stacked db which is nullptr
-  virtual Status FlushWAL(bool /*sync*/) override { return Status::OK(); }
+  Status FlushWAL(bool /*sync*/) override { return Status::OK(); }
 
   std::vector<std::string> live_files_;
   // pair<filename, alive?>
@@ -156,7 +143,7 @@ class TestEnv : public EnvWrapper {
    public:
     explicit DummySequentialFile(bool fail_reads)
         : SequentialFile(), rnd_(5), fail_reads_(fail_reads) {}
-    virtual Status Read(size_t n, Slice* result, char* scratch) override {
+    Status Read(size_t n, Slice* result, char* scratch) override {
       if (fail_reads_) {
         return Status::IOError();
       }
@@ -169,10 +156,11 @@ class TestEnv : public EnvWrapper {
       return Status::OK();
     }
 
-    virtual Status Skip(uint64_t n) override {
+    Status Skip(uint64_t n) override {
       size_left = (n > size_left) ? size_left - n : 0;
       return Status::OK();
     }
+
    private:
     size_t size_left = 200;
     Random rnd_;
@@ -217,9 +205,9 @@ class TestEnv : public EnvWrapper {
     return s;
   }
 
-  virtual Status NewRandomAccessFile(const std::string& fname,
+  Status NewRandomAccessFile(const std::string& fname,
-                                     unique_ptr<RandomAccessFile>* result,
+                             unique_ptr<RandomAccessFile>* result,
-                                     const EnvOptions& options) override {
+                             const EnvOptions& options) override {
     MutexLock l(&mutex_);
     Status s = EnvWrapper::NewRandomAccessFile(fname, result, options);
     if (s.ok()) {
@@ -231,7 +219,7 @@ class TestEnv : public EnvWrapper {
     return s;
   }
 
-  virtual Status DeleteFile(const std::string& fname) override {
+  Status DeleteFile(const std::string& fname) override {
     MutexLock l(&mutex_);
     if (fail_delete_files_) {
       return Status::IOError();
@@ -241,7 +229,7 @@ class TestEnv : public EnvWrapper {
     return EnvWrapper::DeleteFile(fname);
   }
 
-  virtual Status DeleteDir(const std::string& dirname) override {
+  Status DeleteDir(const std::string& dirname) override {
     MutexLock l(&mutex_);
     if (fail_delete_files_) {
       return Status::IOError();
@@ -336,8 +324,8 @@ class TestEnv : public EnvWrapper {
   }
 
   void SetNewDirectoryFailure(bool fail) { new_directory_failure_ = fail; }
-  virtual Status NewDirectory(const std::string& name,
+  Status NewDirectory(const std::string& name,
-                              std::unique_ptr<Directory>* result) override {
+                      std::unique_ptr<Directory>* result) override {
     if (new_directory_failure_) {
       return Status::IOError("SimulatedFailure");
     }

utilities/blob_db/blob_compaction_filter.cc

@@ -22,24 +22,21 @@ class BlobIndexCompactionFilter : public CompactionFilter {
         current_time_(current_time),
         statistics_(statistics) {}
 
-  virtual ~BlobIndexCompactionFilter() {
+  ~BlobIndexCompactionFilter() override {
     RecordTick(statistics_, BLOB_DB_BLOB_INDEX_EXPIRED_COUNT, expired_count_);
     RecordTick(statistics_, BLOB_DB_BLOB_INDEX_EXPIRED_SIZE, expired_size_);
     RecordTick(statistics_, BLOB_DB_BLOB_INDEX_EVICTED_COUNT, evicted_count_);
     RecordTick(statistics_, BLOB_DB_BLOB_INDEX_EVICTED_SIZE, evicted_size_);
   }
 
-  virtual const char* Name() const override {
+  const char* Name() const override { return "BlobIndexCompactionFilter"; }
-    return "BlobIndexCompactionFilter";
-  }
 
   // Filter expired blob indexes regardless of snapshots.
-  virtual bool IgnoreSnapshots() const override { return true; }
+  bool IgnoreSnapshots() const override { return true; }
 
-  virtual Decision FilterV2(int /*level*/, const Slice& key,
+  Decision FilterV2(int /*level*/, const Slice& key, ValueType value_type,
-                            ValueType value_type, const Slice& value,
+                    const Slice& value, std::string* /*new_value*/,
-                            std::string* /*new_value*/,
+                    std::string* /*skip_until*/) const override {
-                            std::string* /*skip_until*/) const override {
     if (value_type != kBlobIndex) {
       return Decision::kKeep;
     }

utilities/blob_db/blob_db_impl.cc

@@ -568,8 +568,8 @@ class BlobDBImpl::BlobInserter : public WriteBatch::Handler {
 
   WriteBatch* batch() { return &batch_; }
 
-  virtual Status PutCF(uint32_t column_family_id, const Slice& key,
+  Status PutCF(uint32_t column_family_id, const Slice& key,
-                       const Slice& value) override {
+               const Slice& value) override {
     if (column_family_id != default_cf_id_) {
       return Status::NotSupported(
           "Blob DB doesn't support non-default column family.");
@@ -579,8 +579,7 @@ class BlobDBImpl::BlobInserter : public WriteBatch::Handler {
     return s;
   }
 
-  virtual Status DeleteCF(uint32_t column_family_id,
+  Status DeleteCF(uint32_t column_family_id, const Slice& key) override {
-                          const Slice& key) override {
     if (column_family_id != default_cf_id_) {
       return Status::NotSupported(
           "Blob DB doesn't support non-default column family.");
@@ -600,17 +599,17 @@ class BlobDBImpl::BlobInserter : public WriteBatch::Handler {
     return s;
   }
 
-  virtual Status SingleDeleteCF(uint32_t /*column_family_id*/,
+  Status SingleDeleteCF(uint32_t /*column_family_id*/,
-                                const Slice& /*key*/) override {
+                        const Slice& /*key*/) override {
     return Status::NotSupported("Not supported operation in blob db.");
   }
 
-  virtual Status MergeCF(uint32_t /*column_family_id*/, const Slice& /*key*/,
+  Status MergeCF(uint32_t /*column_family_id*/, const Slice& /*key*/,
-                         const Slice& /*value*/) override {
+                 const Slice& /*value*/) override {
     return Status::NotSupported("Not supported operation in blob db.");
   }
 
-  virtual void LogData(const Slice& blob) override { batch_.PutLogData(blob); }
+  void LogData(const Slice& blob) override { batch_.PutLogData(blob); }
 };
 
 Status BlobDBImpl::Write(const WriteOptions& options, WriteBatch* updates) {
@@ -1405,7 +1404,7 @@ class BlobDBImpl::GarbageCollectionWriteCallback : public WriteCallback {
                                  SequenceNumber upper_bound)
       : cfd_(cfd), key_(key), upper_bound_(upper_bound) {}
 
-  virtual Status Callback(DB* db) override {
+  Status Callback(DB* db) override {
     auto* db_impl = reinterpret_cast<DBImpl*>(db);
     auto* sv = db_impl->GetAndRefSuperVersion(cfd_);
     SequenceNumber latest_seq = 0;
@@ -1432,7 +1431,7 @@ class BlobDBImpl::GarbageCollectionWriteCallback : public WriteCallback {
     return s;
   }
 
-  virtual bool AllowWriteBatching() override { return false; }
+  bool AllowWriteBatching() override { return false; }
 
  private:
   ColumnFamilyData* cfd_;

utilities/blob_db/blob_db_test.cc

@@ -48,7 +48,7 @@ class BlobDBTest : public testing::Test {
     assert(s.ok());
   }
 
-  ~BlobDBTest() {
+  ~BlobDBTest() override {
     SyncPoint::GetInstance()->ClearAllCallBacks();
     Destroy();
   }
@@ -1234,12 +1234,12 @@ TEST_F(BlobDBTest, InlineSmallValues) {
 
 TEST_F(BlobDBTest, CompactionFilterNotSupported) {
   class TestCompactionFilter : public CompactionFilter {
-    virtual const char *Name() const { return "TestCompactionFilter"; }
+    const char *Name() const override { return "TestCompactionFilter"; }
   };
   class TestCompactionFilterFactory : public CompactionFilterFactory {
-    virtual const char *Name() const { return "TestCompactionFilterFactory"; }
+    const char *Name() const override { return "TestCompactionFilterFactory"; }
-    virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
+    std::unique_ptr<CompactionFilter> CreateCompactionFilter(
-        const CompactionFilter::Context & /*context*/) {
+        const CompactionFilter::Context & /*context*/) override {
       return std::unique_ptr<CompactionFilter>(new TestCompactionFilter());
     }
   };

utilities/cassandra/cassandra_functional_test.cc

@@ -99,15 +99,13 @@ public:
      : purge_ttl_on_expiration_(purge_ttl_on_expiration),
        gc_grace_period_in_seconds_(gc_grace_period_in_seconds) {}
 
- virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
+ std::unique_ptr<CompactionFilter> CreateCompactionFilter(
      const CompactionFilter::Context& /*context*/) override {
    return std::unique_ptr<CompactionFilter>(new CassandraCompactionFilter(
        purge_ttl_on_expiration_, gc_grace_period_in_seconds_));
-  }
+ }
 
-  virtual const char* Name() const override {
+ const char* Name() const override { return "TestCompactionFilterFactory"; }
-    return "TestCompactionFilterFactory";
-  }
 
 private:
   bool purge_ttl_on_expiration_;

utilities/checkpoint/checkpoint_test.cc

@@ -66,7 +66,7 @@ class CheckpointTest : public testing::Test {
     Reopen(options);
   }
 
-  ~CheckpointTest() {
+  ~CheckpointTest() override {
     rocksdb::SyncPoint::GetInstance()->DisableProcessing();
     rocksdb::SyncPoint::GetInstance()->LoadDependency({});
     rocksdb::SyncPoint::GetInstance()->ClearAllCallBacks();

utilities/env_timed.cc

@@ -17,121 +17,118 @@ class TimedEnv : public EnvWrapper {
  public:
   explicit TimedEnv(Env* base_env) : EnvWrapper(base_env) {}
 
-  virtual Status NewSequentialFile(const std::string& fname,
+  Status NewSequentialFile(const std::string& fname,
-                                   std::unique_ptr<SequentialFile>* result,
+                           std::unique_ptr<SequentialFile>* result,
-                                   const EnvOptions& options) override {
+                           const EnvOptions& options) override {
     PERF_TIMER_GUARD(env_new_sequential_file_nanos);
     return EnvWrapper::NewSequentialFile(fname, result, options);
   }
 
-  virtual Status NewRandomAccessFile(const std::string& fname,
+  Status NewRandomAccessFile(const std::string& fname,
-                                     std::unique_ptr<RandomAccessFile>* result,
+                             std::unique_ptr<RandomAccessFile>* result,
-                                     const EnvOptions& options) override {
+                             const EnvOptions& options) override {
     PERF_TIMER_GUARD(env_new_random_access_file_nanos);
     return EnvWrapper::NewRandomAccessFile(fname, result, options);
   }
 
-  virtual Status NewWritableFile(const std::string& fname,
+  Status NewWritableFile(const std::string& fname,
-                                 std::unique_ptr<WritableFile>* result,
+                         std::unique_ptr<WritableFile>* result,
-                                 const EnvOptions& options) override {
+                         const EnvOptions& options) override {
     PERF_TIMER_GUARD(env_new_writable_file_nanos);
     return EnvWrapper::NewWritableFile(fname, result, options);
   }
 
-  virtual Status ReuseWritableFile(const std::string& fname,
+  Status ReuseWritableFile(const std::string& fname,
-                                   const std::string& old_fname,
+                           const std::string& old_fname,
-                                   std::unique_ptr<WritableFile>* result,
+                           std::unique_ptr<WritableFile>* result,
-                                   const EnvOptions& options) override {
+                           const EnvOptions& options) override {
     PERF_TIMER_GUARD(env_reuse_writable_file_nanos);
     return EnvWrapper::ReuseWritableFile(fname, old_fname, result, options);
   }
 
-  virtual Status NewRandomRWFile(const std::string& fname,
+  Status NewRandomRWFile(const std::string& fname,
-                                 std::unique_ptr<RandomRWFile>* result,
+                         std::unique_ptr<RandomRWFile>* result,
-                                 const EnvOptions& options) override {
+                         const EnvOptions& options) override {
     PERF_TIMER_GUARD(env_new_random_rw_file_nanos);
     return EnvWrapper::NewRandomRWFile(fname, result, options);
   }
 
-  virtual Status NewDirectory(const std::string& name,
+  Status NewDirectory(const std::string& name,
-                              std::unique_ptr<Directory>* result) override {
+                      std::unique_ptr<Directory>* result) override {
     PERF_TIMER_GUARD(env_new_directory_nanos);
     return EnvWrapper::NewDirectory(name, result);
   }
 
-  virtual Status FileExists(const std::string& fname) override {
+  Status FileExists(const std::string& fname) override {
     PERF_TIMER_GUARD(env_file_exists_nanos);
     return EnvWrapper::FileExists(fname);
   }
 
-  virtual Status GetChildren(const std::string& dir,
+  Status GetChildren(const std::string& dir,
-                             std::vector<std::string>* result) override {
+                     std::vector<std::string>* result) override {
     PERF_TIMER_GUARD(env_get_children_nanos);
     return EnvWrapper::GetChildren(dir, result);
   }
 
-  virtual Status GetChildrenFileAttributes(
+  Status GetChildrenFileAttributes(
       const std::string& dir, std::vector<FileAttributes>* result) override {
     PERF_TIMER_GUARD(env_get_children_file_attributes_nanos);
     return EnvWrapper::GetChildrenFileAttributes(dir, result);
   }
 
-  virtual Status DeleteFile(const std::string& fname) override {
+  Status DeleteFile(const std::string& fname) override {
     PERF_TIMER_GUARD(env_delete_file_nanos);
     return EnvWrapper::DeleteFile(fname);
   }
 
-  virtual Status CreateDir(const std::string& dirname) override {
+  Status CreateDir(const std::string& dirname) override {
     PERF_TIMER_GUARD(env_create_dir_nanos);
     return EnvWrapper::CreateDir(dirname);
   }
 
-  virtual Status CreateDirIfMissing(const std::string& dirname) override {
+  Status CreateDirIfMissing(const std::string& dirname) override {
     PERF_TIMER_GUARD(env_create_dir_if_missing_nanos);
     return EnvWrapper::CreateDirIfMissing(dirname);
   }
 
-  virtual Status DeleteDir(const std::string& dirname) override {
+  Status DeleteDir(const std::string& dirname) override {
     PERF_TIMER_GUARD(env_delete_dir_nanos);
     return EnvWrapper::DeleteDir(dirname);
   }
 
-  virtual Status GetFileSize(const std::string& fname,
+  Status GetFileSize(const std::string& fname, uint64_t* file_size) override {
-                             uint64_t* file_size) override {
     PERF_TIMER_GUARD(env_get_file_size_nanos);
     return EnvWrapper::GetFileSize(fname, file_size);
   }
 
-  virtual Status GetFileModificationTime(const std::string& fname,
+  Status GetFileModificationTime(const std::string& fname,
-                                         uint64_t* file_mtime) override {
+                                 uint64_t* file_mtime) override {
     PERF_TIMER_GUARD(env_get_file_modification_time_nanos);
     return EnvWrapper::GetFileModificationTime(fname, file_mtime);
   }
 
-  virtual Status RenameFile(const std::string& src,
+  Status RenameFile(const std::string& src, const std::string& dst) override {
-                            const std::string& dst) override {
     PERF_TIMER_GUARD(env_rename_file_nanos);
     return EnvWrapper::RenameFile(src, dst);
   }
 
-  virtual Status LinkFile(const std::string& src,
+  Status LinkFile(const std::string& src, const std::string& dst) override {
-                          const std::string& dst) override {
     PERF_TIMER_GUARD(env_link_file_nanos);
     return EnvWrapper::LinkFile(src, dst);
   }
 
-  virtual Status LockFile(const std::string& fname, FileLock** lock) override {
+  Status LockFile(const std::string& fname, FileLock** lock) override {
     PERF_TIMER_GUARD(env_lock_file_nanos);
     return EnvWrapper::LockFile(fname, lock);
   }
 
-  virtual Status UnlockFile(FileLock* lock) override {
+  Status UnlockFile(FileLock* lock) override {
     PERF_TIMER_GUARD(env_unlock_file_nanos);
     return EnvWrapper::UnlockFile(lock);
   }
 
-  virtual Status NewLogger(const std::string& fname,
+  Status NewLogger(const std::string& fname,
-                           std::shared_ptr<Logger>* result) override {
+                   std::shared_ptr<Logger>* result) override {
     PERF_TIMER_GUARD(env_new_logger_nanos);
     return EnvWrapper::NewLogger(fname, result);
   }

utilities/merge_operators/max.cc

@@ -19,8 +19,8 @@ namespace {  // anonymous namespace
 // Slice::compare
 class MaxOperator : public MergeOperator {
  public:
-  virtual bool FullMergeV2(const MergeOperationInput& merge_in,
+  bool FullMergeV2(const MergeOperationInput& merge_in,
-                           MergeOperationOutput* merge_out) const override {
+                   MergeOperationOutput* merge_out) const override {
     Slice& max = merge_out->existing_operand;
     if (merge_in.existing_value) {
       max = Slice(merge_in.existing_value->data(),
@@ -38,9 +38,9 @@ class MaxOperator : public MergeOperator {
     return true;
   }
 
-  virtual bool PartialMerge(const Slice& /*key*/, const Slice& left_operand,
+  bool PartialMerge(const Slice& /*key*/, const Slice& left_operand,
-                            const Slice& right_operand, std::string* new_value,
+                    const Slice& right_operand, std::string* new_value,
-                            Logger* /*logger*/) const override {
+                    Logger* /*logger*/) const override {
     if (left_operand.compare(right_operand) >= 0) {
       new_value->assign(left_operand.data(), left_operand.size());
     } else {
@@ -49,10 +49,10 @@ class MaxOperator : public MergeOperator {
     return true;
   }
 
-  virtual bool PartialMergeMulti(const Slice& /*key*/,
+  bool PartialMergeMulti(const Slice& /*key*/,
-                                 const std::deque<Slice>& operand_list,
+                         const std::deque<Slice>& operand_list,
-                                 std::string* new_value,
+                         std::string* new_value,
-                                 Logger* /*logger*/) const override {
+                         Logger* /*logger*/) const override {
     Slice max;
     for (const auto& operand : operand_list) {
       if (max.compare(operand) < 0) {
@@ -64,7 +64,7 @@ class MaxOperator : public MergeOperator {
     return true;
   }
 
-  virtual const char* Name() const override { return "MaxOperator"; }
+  const char* Name() const override { return "MaxOperator"; }
 };
 
 }  // end of anonymous namespace

utilities/merge_operators/put.cc

@@ -22,10 +22,9 @@ namespace { // anonymous namespace
 // From the client-perspective, semantics are the same.
 class PutOperator : public MergeOperator {
  public:
-  virtual bool FullMerge(const Slice& /*key*/, const Slice* /*existing_value*/,
+  bool FullMerge(const Slice& /*key*/, const Slice* /*existing_value*/,
-                         const std::deque<std::string>& operand_sequence,
+                 const std::deque<std::string>& operand_sequence,
-                         std::string* new_value,
+                 std::string* new_value, Logger* /*logger*/) const override {
-                         Logger* /*logger*/) const override {
     // Put basically only looks at the current/latest value
     assert(!operand_sequence.empty());
     assert(new_value != nullptr);
@@ -33,38 +32,36 @@ class PutOperator : public MergeOperator {
     return true;
   }
 
-  virtual bool PartialMerge(const Slice& /*key*/, const Slice& /*left_operand*/,
+  bool PartialMerge(const Slice& /*key*/, const Slice& /*left_operand*/,
-                            const Slice& right_operand, std::string* new_value,
+                    const Slice& right_operand, std::string* new_value,
-                            Logger* /*logger*/) const override {
+                    Logger* /*logger*/) const override {
     new_value->assign(right_operand.data(), right_operand.size());
     return true;
   }
 
   using MergeOperator::PartialMergeMulti;
-  virtual bool PartialMergeMulti(const Slice& /*key*/,
+  bool PartialMergeMulti(const Slice& /*key*/,
-                                 const std::deque<Slice>& operand_list,
+                         const std::deque<Slice>& operand_list,
-                                 std::string* new_value,
+                         std::string* new_value,
-                                 Logger* /*logger*/) const override {
+                         Logger* /*logger*/) const override {
     new_value->assign(operand_list.back().data(), operand_list.back().size());
     return true;
   }
 
-  virtual const char* Name() const override {
+  const char* Name() const override { return "PutOperator"; }
-    return "PutOperator";
-  }
 };
 
 class PutOperatorV2 : public PutOperator {
-  virtual bool FullMerge(const Slice& /*key*/, const Slice* /*existing_value*/,
+  bool FullMerge(const Slice& /*key*/, const Slice* /*existing_value*/,
-                         const std::deque<std::string>& /*operand_sequence*/,
+                 const std::deque<std::string>& /*operand_sequence*/,
-                         std::string* /*new_value*/,
+                 std::string* /*new_value*/,
-                         Logger* /*logger*/) const override {
+                 Logger* /*logger*/) const override {
     assert(false);
     return false;
   }
 
-  virtual bool FullMergeV2(const MergeOperationInput& merge_in,
+  bool FullMergeV2(const MergeOperationInput& merge_in,
-                           MergeOperationOutput* merge_out) const override {
+                   MergeOperationOutput* merge_out) const override {
     // Put basically only looks at the current/latest value
     assert(!merge_in.operand_list.empty());
     merge_out->existing_operand = merge_in.operand_list.back();

utilities/merge_operators/uint64add.cc

@@ -20,9 +20,9 @@ namespace { // anonymous namespace
 // Implemented as an AssociativeMergeOperator for simplicity and example.
 class UInt64AddOperator : public AssociativeMergeOperator {
  public:
-  virtual bool Merge(const Slice& /*key*/, const Slice* existing_value,
+  bool Merge(const Slice& /*key*/, const Slice* existing_value,
-                     const Slice& value, std::string* new_value,
+             const Slice& value, std::string* new_value,
-                     Logger* logger) const override {
+             Logger* logger) const override {
     uint64_t orig_value = 0;
     if (existing_value){
       orig_value = DecodeInteger(*existing_value, logger);
@@ -36,9 +36,7 @@ class UInt64AddOperator : public AssociativeMergeOperator {
     return true;  // Return true always since corruption will be treated as 0
   }
 
-  virtual const char* Name() const override {
+  const char* Name() const override { return "UInt64AddOperator"; }
-    return "UInt64AddOperator";
-  }
 
  private:
   // Takes the string and decodes it into a uint64_t

utilities/options/options_util_test.cc

@@ -98,11 +98,11 @@ namespace {
 class DummyTableFactory : public TableFactory {
  public:
   DummyTableFactory() {}
-  virtual ~DummyTableFactory() {}
+  ~DummyTableFactory() override {}
 
-  virtual const char* Name() const override { return "DummyTableFactory"; }
+  const char* Name() const override { return "DummyTableFactory"; }
 
-  virtual Status NewTableReader(
+  Status NewTableReader(
       const TableReaderOptions& /*table_reader_options*/,
       std::unique_ptr<RandomAccessFileReader>&& /*file*/,
       uint64_t /*file_size*/, std::unique_ptr<TableReader>* /*table_reader*/,
@@ -110,20 +110,20 @@ class DummyTableFactory : public TableFactory {
     return Status::NotSupported();
   }
 
-  virtual TableBuilder* NewTableBuilder(
+  TableBuilder* NewTableBuilder(
       const TableBuilderOptions& /*table_builder_options*/,
       uint32_t /*column_family_id*/,
       WritableFileWriter* /*file*/) const override {
     return nullptr;
   }
 
-  virtual Status SanitizeOptions(
+  Status SanitizeOptions(
       const DBOptions& /*db_opts*/,
       const ColumnFamilyOptions& /*cf_opts*/) const override {
     return Status::NotSupported();
   }
 
-  virtual std::string GetPrintableTableOptions() const override { return ""; }
+  std::string GetPrintableTableOptions() const override { return ""; }
 
   Status GetOptionString(std::string* /*opt_string*/,
                          const std::string& /*delimiter*/) const override {
@@ -134,39 +134,39 @@ class DummyTableFactory : public TableFactory {
 class DummyMergeOperator : public MergeOperator {
  public:
   DummyMergeOperator() {}
-  virtual ~DummyMergeOperator() {}
+  ~DummyMergeOperator() override {}
 
-  virtual bool FullMergeV2(const MergeOperationInput& /*merge_in*/,
+  bool FullMergeV2(const MergeOperationInput& /*merge_in*/,
-                           MergeOperationOutput* /*merge_out*/) const override {
+                   MergeOperationOutput* /*merge_out*/) const override {
     return false;
   }
 
-  virtual bool PartialMergeMulti(const Slice& /*key*/,
+  bool PartialMergeMulti(const Slice& /*key*/,
-                                 const std::deque<Slice>& /*operand_list*/,
+                         const std::deque<Slice>& /*operand_list*/,
-                                 std::string* /*new_value*/,
+                         std::string* /*new_value*/,
-                                 Logger* /*logger*/) const override {
+                         Logger* /*logger*/) const override {
     return false;
   }
 
-  virtual const char* Name() const override { return "DummyMergeOperator"; }
+  const char* Name() const override { return "DummyMergeOperator"; }
 };
 
 class DummySliceTransform : public SliceTransform {
  public:
   DummySliceTransform() {}
-  virtual ~DummySliceTransform() {}
+  ~DummySliceTransform() override {}
 
   // Return the name of this transformation.
-  virtual const char* Name() const { return "DummySliceTransform"; }
+  const char* Name() const override { return "DummySliceTransform"; }
 
   // transform a src in domain to a dst in the range
-  virtual Slice Transform(const Slice& src) const { return src; }
+  Slice Transform(const Slice& src) const override { return src; }
 
   // determine whether this is a valid src upon the function applies
-  virtual bool InDomain(const Slice& /*src*/) const { return false; }
+  bool InDomain(const Slice& /*src*/) const override { return false; }
 
   // determine whether dst=Transform(src) for some src
-  virtual bool InRange(const Slice& /*dst*/) const { return false; }
+  bool InRange(const Slice& /*dst*/) const override { return false; }
 };
 
 }  // namespace

utilities/persistent_cache/hash_table_test.cc

@@ -20,7 +20,7 @@
 namespace rocksdb {
 
 struct HashTableTest : public testing::Test {
-  ~HashTableTest() { map_.Clear(&HashTableTest::ClearNode); }
+  ~HashTableTest() override { map_.Clear(&HashTableTest::ClearNode); }
 
   struct Node {
     Node() {}
@@ -49,7 +49,9 @@ struct HashTableTest : public testing::Test {
 };
 
 struct EvictableHashTableTest : public testing::Test {
-  ~EvictableHashTableTest() { map_.Clear(&EvictableHashTableTest::ClearNode); }
+  ~EvictableHashTableTest() override {
+    map_.Clear(&EvictableHashTableTest::ClearNode);
+  }
 
   struct Node : LRUElement<Node> {
     Node() {}

utilities/simulator_cache/sim_cache.cc

@@ -160,18 +160,16 @@ class SimCacheImpl : public SimCache {
         hit_times_(0),
         stats_(nullptr) {}
 
-  virtual ~SimCacheImpl() {}
+  ~SimCacheImpl() override {}
-  virtual void SetCapacity(size_t capacity) override {
+  void SetCapacity(size_t capacity) override { cache_->SetCapacity(capacity); }
-    cache_->SetCapacity(capacity);
-  }
 
-  virtual void SetStrictCapacityLimit(bool strict_capacity_limit) override {
+  void SetStrictCapacityLimit(bool strict_capacity_limit) override {
     cache_->SetStrictCapacityLimit(strict_capacity_limit);
   }
 
-  virtual Status Insert(const Slice& key, void* value, size_t charge,
+  Status Insert(const Slice& key, void* value, size_t charge,
-                        void (*deleter)(const Slice& key, void* value),
+                void (*deleter)(const Slice& key, void* value), Handle** handle,
-                        Handle** handle, Priority priority) override {
+                Priority priority) override {
     // The handle and value passed in are for real cache, so we pass nullptr
     // to key_only_cache_ for both instead. Also, the deleter function pointer
     // will be called by user to perform some external operation which should
@@ -191,7 +189,7 @@ class SimCacheImpl : public SimCache {
     return cache_->Insert(key, value, charge, deleter, handle, priority);
   }
 
-  virtual Handle* Lookup(const Slice& key, Statistics* stats) override {
+  Handle* Lookup(const Slice& key, Statistics* stats) override {
     Handle* h = key_only_cache_->Lookup(key);
     if (h != nullptr) {
       key_only_cache_->Release(h);
@@ -207,79 +205,75 @@ class SimCacheImpl : public SimCache {
     return cache_->Lookup(key, stats);
   }
 
-  virtual bool Ref(Handle* handle) override { return cache_->Ref(handle); }
+  bool Ref(Handle* handle) override { return cache_->Ref(handle); }
 
-  virtual bool Release(Handle* handle, bool force_erase = false) override {
+  bool Release(Handle* handle, bool force_erase = false) override {
     return cache_->Release(handle, force_erase);
   }
 
-  virtual void Erase(const Slice& key) override {
+  void Erase(const Slice& key) override {
     cache_->Erase(key);
     key_only_cache_->Erase(key);
   }
 
-  virtual void* Value(Handle* handle) override { return cache_->Value(handle); }
+  void* Value(Handle* handle) override { return cache_->Value(handle); }
 
-  virtual uint64_t NewId() override { return cache_->NewId(); }
+  uint64_t NewId() override { return cache_->NewId(); }
 
-  virtual size_t GetCapacity() const override { return cache_->GetCapacity(); }
+  size_t GetCapacity() const override { return cache_->GetCapacity(); }
 
-  virtual bool HasStrictCapacityLimit() const override {
+  bool HasStrictCapacityLimit() const override {
     return cache_->HasStrictCapacityLimit();
   }
 
-  virtual size_t GetUsage() const override { return cache_->GetUsage(); }
+  size_t GetUsage() const override { return cache_->GetUsage(); }
 
-  virtual size_t GetUsage(Handle* handle) const override {
+  size_t GetUsage(Handle* handle) const override {
     return cache_->GetUsage(handle);
   }
 
-  virtual size_t GetPinnedUsage() const override {
+  size_t GetPinnedUsage() const override { return cache_->GetPinnedUsage(); }
-    return cache_->GetPinnedUsage();
-  }
 
-  virtual void DisownData() override {
+  void DisownData() override {
     cache_->DisownData();
     key_only_cache_->DisownData();
   }
 
-  virtual void ApplyToAllCacheEntries(void (*callback)(void*, size_t),
+  void ApplyToAllCacheEntries(void (*callback)(void*, size_t),
-                                      bool thread_safe) override {
+                              bool thread_safe) override {
     // only apply to _cache since key_only_cache doesn't hold value
     cache_->ApplyToAllCacheEntries(callback, thread_safe);
   }
 
-  virtual void EraseUnRefEntries() override {
+  void EraseUnRefEntries() override {
     cache_->EraseUnRefEntries();
     key_only_cache_->EraseUnRefEntries();
   }
 
-  virtual size_t GetSimCapacity() const override {
+  size_t GetSimCapacity() const override {
     return key_only_cache_->GetCapacity();
   }
-  virtual size_t GetSimUsage() const override {
+  size_t GetSimUsage() const override { return key_only_cache_->GetUsage(); }
-    return key_only_cache_->GetUsage();
+  void SetSimCapacity(size_t capacity) override {
-  }
-  virtual void SetSimCapacity(size_t capacity) override {
     key_only_cache_->SetCapacity(capacity);
   }
 
-  virtual uint64_t get_miss_counter() const override {
+  uint64_t get_miss_counter() const override {
     return miss_times_.load(std::memory_order_relaxed);
   }
 
-  virtual uint64_t get_hit_counter() const override {
+  uint64_t get_hit_counter() const override {
     return hit_times_.load(std::memory_order_relaxed);
   }
 
-  virtual void reset_counter() override {
+  void reset_counter() override {
     miss_times_.store(0, std::memory_order_relaxed);
     hit_times_.store(0, std::memory_order_relaxed);
     SetTickerCount(stats_, SIM_BLOCK_CACHE_HIT, 0);
     SetTickerCount(stats_, SIM_BLOCK_CACHE_MISS, 0);
   }
 
-  virtual std::string ToString() const override {
+  std::string ToString() const override {
     std::string res;
     res.append("SimCache MISSes: " + std::to_string(get_miss_counter()) + "\n");
     res.append("SimCache HITs:    " + std::to_string(get_hit_counter()) + "\n");
@@ -291,7 +285,7 @@ class SimCacheImpl : public SimCache {
     return res;
   }
 
-  virtual std::string GetPrintableOptions() const override {
+  std::string GetPrintableOptions() const override {
     std::string ret;
     ret.reserve(20000);
     ret.append("    cache_options:\n");
@@ -301,18 +295,15 @@ class SimCacheImpl : public SimCache {
     return ret;
   }
 
-  virtual Status StartActivityLogging(const std::string& activity_log_file,
+  Status StartActivityLogging(const std::string& activity_log_file, Env* env,
-                                      Env* env,
+                              uint64_t max_logging_size = 0) override {
-                                      uint64_t max_logging_size = 0) override {
     return cache_activity_logger_.StartLogging(activity_log_file, env,
                                                max_logging_size);
   }
 
-  virtual void StopActivityLogging() override {
+  void StopActivityLogging() override { cache_activity_logger_.StopLogging(); }
-    cache_activity_logger_.StopLogging();
-  }
 
-  virtual Status GetActivityLoggingStatus() override {
+  Status GetActivityLoggingStatus() override {
     return cache_activity_logger_.bg_status();
   }
 

utilities/transactions/optimistic_transaction_test.cc

@@ -37,7 +37,7 @@ class OptimisticTransactionTest : public testing::Test {
     DestroyDB(dbname, options);
     Open();
   }
-  ~OptimisticTransactionTest() {
+  ~OptimisticTransactionTest() override {
     delete txn_db;
     DestroyDB(dbname, options);
   }

utilities/transactions/pessimistic_transaction.cc

@@ -459,18 +459,17 @@ Status PessimisticTransaction::LockBatch(WriteBatch* batch,
       }
     }
 
-    virtual Status PutCF(uint32_t column_family_id, const Slice& key,
+    Status PutCF(uint32_t column_family_id, const Slice& key,
-                         const Slice& /* unused */) override {
+                 const Slice& /* unused */) override {
       RecordKey(column_family_id, key);
       return Status::OK();
     }
-    virtual Status MergeCF(uint32_t column_family_id, const Slice& key,
+    Status MergeCF(uint32_t column_family_id, const Slice& key,
-                           const Slice& /* unused */) override {
+                   const Slice& /* unused */) override {
       RecordKey(column_family_id, key);
       return Status::OK();
     }
-    virtual Status DeleteCF(uint32_t column_family_id,
+    Status DeleteCF(uint32_t column_family_id, const Slice& key) override {
-                            const Slice& key) override {
       RecordKey(column_family_id, key);
       return Status::OK();
     }

utilities/transactions/transaction_db_mutex_impl.cc

@@ -19,7 +19,7 @@ namespace rocksdb {
 class TransactionDBMutexImpl : public TransactionDBMutex {
  public:
   TransactionDBMutexImpl() {}
-  ~TransactionDBMutexImpl() {}
+  ~TransactionDBMutexImpl() override {}
 
   Status Lock() override;
 
@@ -36,7 +36,7 @@ class TransactionDBMutexImpl : public TransactionDBMutex {
 class TransactionDBCondVarImpl : public TransactionDBCondVar {
  public:
   TransactionDBCondVarImpl() {}
-  ~TransactionDBCondVarImpl() {}
+  ~TransactionDBCondVarImpl() override {}
 
   Status Wait(std::shared_ptr<TransactionDBMutex> mutex) override;
 

utilities/transactions/transaction_test.cc

@@ -4791,7 +4791,7 @@ TEST_P(TransactionTest, SetSnapshotOnNextOperationWithNotification) {
     explicit Notifier(const Snapshot** snapshot_ptr)
         : snapshot_ptr_(snapshot_ptr) {}
 
-    void SnapshotCreated(const Snapshot* newSnapshot) {
+    void SnapshotCreated(const Snapshot* newSnapshot) override {
       *snapshot_ptr_ = newSnapshot;
     }
   };
@@ -5266,15 +5266,13 @@ TEST_P(TransactionTest, Optimizations) {
 class ThreeBytewiseComparator : public Comparator {
  public:
   ThreeBytewiseComparator() {}
-  virtual const char* Name() const override {
+  const char* Name() const override { return "test.ThreeBytewiseComparator"; }
-    return "test.ThreeBytewiseComparator";
+  int Compare(const Slice& a, const Slice& b) const override {
-  }
-  virtual int Compare(const Slice& a, const Slice& b) const override {
     Slice na = Slice(a.data(), a.size() < 3 ? a.size() : 3);
     Slice nb = Slice(b.data(), b.size() < 3 ? b.size() : 3);
     return na.compare(nb);
   }
-  virtual bool Equal(const Slice& a, const Slice& b) const override {
+  bool Equal(const Slice& a, const Slice& b) const override {
     Slice na = Slice(a.data(), a.size() < 3 ? a.size() : 3);
     Slice nb = Slice(b.data(), b.size() < 3 ? b.size() : 3);
     return na == nb;

utilities/transactions/write_prepared_transaction_test.cc

@@ -330,7 +330,7 @@ class WritePreparedTxnDBMock : public WritePreparedTxnDB {
   void TakeSnapshot(SequenceNumber seq) { snapshots_.push_back(seq); }
 
  protected:
-  virtual const std::vector<SequenceNumber> GetSnapshotListFromDB(
+  const std::vector<SequenceNumber> GetSnapshotListFromDB(
       SequenceNumber /* unused */) override {
     return snapshots_;
   }

utilities/transactions/write_prepared_txn.cc

@@ -185,7 +185,7 @@ Status WritePreparedTxn::CommitInternal() {
    public:
     explicit PublishSeqPreReleaseCallback(DBImpl* db_impl)
         : db_impl_(db_impl) {}
-    virtual Status Callback(SequenceNumber seq, bool is_mem_disabled) override {
+    Status Callback(SequenceNumber seq, bool is_mem_disabled) override {
 #ifdef NDEBUG
       (void)is_mem_disabled;
 #endif
@@ -311,7 +311,7 @@ Status WritePreparedTxn::RollbackInternal() {
     }
 
    protected:
-    virtual bool WriteAfterCommit() const override { return false; }
+    bool WriteAfterCommit() const override { return false; }
   } rollback_handler(db_impl_, wpt_db_, read_at_seq, &rollback_batch,
                      *cf_comp_map_shared_ptr.get(), *cf_map_shared_ptr.get(),
                      wpt_db_->txn_db_options_.rollback_merge_operands);

utilities/transactions/write_prepared_txn_db.cc

@@ -64,8 +64,7 @@ Status WritePreparedTxnDB::Initialize(
    public:
     explicit CommitSubBatchPreReleaseCallback(WritePreparedTxnDB* db)
         : db_(db) {}
-    virtual Status Callback(SequenceNumber commit_seq,
+    Status Callback(SequenceNumber commit_seq, bool is_mem_disabled) override {
-                            bool is_mem_disabled) override {
 #ifdef NDEBUG
       (void)is_mem_disabled;
 #endif