Revert "comment out unused parameters"

Summary:
This reverts the previous commit 1d7048c598, which broke the build.

Did a `git revert 1d7048c`.
Closes https://github.com/facebook/rocksdb/pull/2627

Differential Revision: D5476473

Pulled By: sagar0

fbshipit-source-id: 4756ff5c0dfc88c17eceb00e02c36176de728d06

cache/cache_test.cc

@@ -40,9 +40,9 @@ static int DecodeValue(void* v) {
 const std::string kLRU = "lru";
 const std::string kClock = "clock";
 
-void dumbDeleter(const Slice& /*key*/, void* /*value*/) {}
+void dumbDeleter(const Slice& key, void* value) {}
 
-void eraseDeleter(const Slice& /*key*/, void* value) {
+void eraseDeleter(const Slice& key, void* value) {
   Cache* cache = reinterpret_cast<Cache*>(value);
   cache->Erase("foo");
 }
@@ -470,7 +470,7 @@ class Value {
 };
 
 namespace {
-void deleter(const Slice& /*key*/, void* value) {
+void deleter(const Slice& key, void* value) {
   delete static_cast<Value *>(value);
 }
 }  // namespace

cache/clock_cache.cc

@@ -581,7 +581,7 @@ Status ClockCacheShard::Insert(const Slice& key, uint32_t hash, void* value,
                                size_t charge,
                                void (*deleter)(const Slice& key, void* value),
                                Cache::Handle** out_handle,
-                               Cache::Priority /*priority*/) {
+                               Cache::Priority priority) {
   CleanupContext context;
   HashTable::accessor accessor;
   char* key_data = new char[key.size()];

cache/sharded_cache.cc

@@ -53,7 +53,7 @@ Status ShardedCache::Insert(const Slice& key, void* value, size_t charge,
       ->Insert(key, hash, value, charge, deleter, handle, priority);
 }
 
-Cache::Handle* ShardedCache::Lookup(const Slice& key, Statistics* /*stats*/) {
+Cache::Handle* ShardedCache::Lookup(const Slice& key, Statistics* stats) {
   uint32_t hash = HashSlice(key);
   return GetShard(Shard(hash))->Lookup(key, hash);
 }

db/builder.cc

@@ -61,10 +61,10 @@ TableBuilder* NewTableBuilder(
 
 Status BuildTable(
     const std::string& dbname, Env* env, const ImmutableCFOptions& ioptions,
-    const MutableCFOptions& /*mutable_cf_options*/,
+    const MutableCFOptions& mutable_cf_options, const EnvOptions& env_options,
-    const EnvOptions& env_options, TableCache* table_cache,
+    TableCache* table_cache, InternalIterator* iter,
-    InternalIterator* iter, std::unique_ptr<InternalIterator> range_del_iter,
+    std::unique_ptr<InternalIterator> range_del_iter, FileMetaData* meta,
-    FileMetaData* meta, const InternalKeyComparator& internal_comparator,
+    const InternalKeyComparator& internal_comparator,
     const std::vector<std::unique_ptr<IntTblPropCollectorFactory>>*
         int_tbl_prop_collector_factories,
     uint32_t column_family_id, const std::string& column_family_name,

db/c.cc

@@ -240,7 +240,7 @@ struct rocksdb_comparator_t : public Comparator {
   // No-ops since the C binding does not support key shortening methods.
   virtual void FindShortestSeparator(std::string*,
                                      const Slice&) const override {}
-  virtual void FindShortSuccessor(std::string* /*key*/) const override {}
+  virtual void FindShortSuccessor(std::string* key) const override {}
 };
 
 struct rocksdb_filterpolicy_t : public FilterPolicy {
@@ -355,7 +355,7 @@ struct rocksdb_mergeoperator_t : public MergeOperator {
   virtual bool PartialMergeMulti(const Slice& key,
                                  const std::deque<Slice>& operand_list,
                                  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);
@@ -2106,8 +2106,8 @@ void rocksdb_options_set_level0_stop_writes_trigger(
   opt->rep.level0_stop_writes_trigger = n;
 }
 
-void rocksdb_options_set_max_mem_compaction_level(rocksdb_options_t* /*opt*/,
+void rocksdb_options_set_max_mem_compaction_level(rocksdb_options_t* opt,
-                                                  int /*n*/) {}
+                                                  int n) {}
 
 void rocksdb_options_set_wal_recovery_mode(rocksdb_options_t* opt,int mode) {
   opt->rep.wal_recovery_mode = static_cast<WALRecoveryMode>(mode);
@@ -2171,8 +2171,8 @@ void rocksdb_options_set_manifest_preallocation_size(
 }
 
 // noop
-void rocksdb_options_set_purge_redundant_kvs_while_flush(
+void rocksdb_options_set_purge_redundant_kvs_while_flush(rocksdb_options_t* opt,
-    rocksdb_options_t* /*opt*/, unsigned char /*v*/) {}
+                                                         unsigned char v) {}
 
 void rocksdb_options_set_use_direct_reads(rocksdb_options_t* opt,
                                           unsigned char v) {
@@ -2332,7 +2332,7 @@ void rocksdb_options_set_table_cache_numshardbits(
 }
 
 void rocksdb_options_set_table_cache_remove_scan_count_limit(
-    rocksdb_options_t* /*opt*/, int /*v*/) {
+    rocksdb_options_t* opt, int v) {
   // this option is deprecated
 }
 
@@ -2836,7 +2836,7 @@ rocksdb_sstfilewriter_t* rocksdb_sstfilewriter_create(
 
 rocksdb_sstfilewriter_t* rocksdb_sstfilewriter_create_with_comparator(
     const rocksdb_envoptions_t* env, const rocksdb_options_t* io_options,
-    const rocksdb_comparator_t* /*comparator*/) {
+    const rocksdb_comparator_t* comparator) {
   rocksdb_sstfilewriter_t* writer = new rocksdb_sstfilewriter_t;
   writer->rep = new SstFileWriter(env->rep, io_options->rep);
   return writer;

db/column_family_test.cc

@@ -1168,14 +1168,13 @@ TEST_F(ColumnFamilyTest, MemtableNotSupportSnapshot) {
 #endif  // !ROCKSDB_LITE
 
 class TestComparator : public Comparator {
-  int Compare(const rocksdb::Slice& /*a*/,
+  int Compare(const rocksdb::Slice& a, const rocksdb::Slice& b) const override {
-              const rocksdb::Slice& /*b*/) const override {
     return 0;
   }
   const char* Name() const override { return "Test"; }
-  void FindShortestSeparator(std::string* /*start*/,
+  void FindShortestSeparator(std::string* start,
-                             const rocksdb::Slice& /*limit*/) const override {}
+                             const rocksdb::Slice& limit) const override {}
-  void FindShortSuccessor(std::string* /*key*/) const override {}
+  void FindShortSuccessor(std::string* key) const override {}
 };
 
 static TestComparator third_comparator;
@@ -1347,7 +1346,7 @@ TEST_F(ColumnFamilyTest, MultipleManualCompactions) {
        {"ColumnFamilyTest::MultiManual:2", "ColumnFamilyTest::MultiManual:5"},
        {"ColumnFamilyTest::MultiManual:2", "ColumnFamilyTest::MultiManual:3"}});
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
-      "DBImpl::BackgroundCompaction:NonTrivial:AfterRun", [&](void* /*arg*/) {
+      "DBImpl::BackgroundCompaction:NonTrivial:AfterRun", [&](void* arg) {
         if (cf_1_1) {
           TEST_SYNC_POINT("ColumnFamilyTest::MultiManual:4");
           cf_1_1 = false;
@@ -1440,7 +1439,7 @@ TEST_F(ColumnFamilyTest, AutomaticAndManualCompactions) {
        {"ColumnFamilyTest::AutoManual:2", "ColumnFamilyTest::AutoManual:5"},
        {"ColumnFamilyTest::AutoManual:2", "ColumnFamilyTest::AutoManual:3"}});
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
-      "DBImpl::BackgroundCompaction:NonTrivial:AfterRun", [&](void* /*arg*/) {
+      "DBImpl::BackgroundCompaction:NonTrivial:AfterRun", [&](void* arg) {
         if (cf_1_1) {
           cf_1_1 = false;
           TEST_SYNC_POINT("ColumnFamilyTest::AutoManual:4");
@@ -1541,7 +1540,7 @@ TEST_F(ColumnFamilyTest, ManualAndAutomaticCompactions) {
        {"ColumnFamilyTest::ManualAuto:5", "ColumnFamilyTest::ManualAuto:2"},
        {"ColumnFamilyTest::ManualAuto:2", "ColumnFamilyTest::ManualAuto:3"}});
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
-      "DBImpl::BackgroundCompaction:NonTrivial:AfterRun", [&](void* /*arg*/) {
+      "DBImpl::BackgroundCompaction:NonTrivial:AfterRun", [&](void* arg) {
         if (cf_1_1) {
           TEST_SYNC_POINT("ColumnFamilyTest::ManualAuto:4");
           cf_1_1 = false;
@@ -1634,7 +1633,7 @@ TEST_F(ColumnFamilyTest, SameCFManualManualCompactions) {
        {"ColumnFamilyTest::ManualManual:1",
         "ColumnFamilyTest::ManualManual:3"}});
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
-      "DBImpl::BackgroundCompaction:NonTrivial:AfterRun", [&](void* /*arg*/) {
+      "DBImpl::BackgroundCompaction:NonTrivial:AfterRun", [&](void* arg) {
         if (cf_1_1) {
           TEST_SYNC_POINT("ColumnFamilyTest::ManualManual:4");
           cf_1_1 = false;
@@ -1732,7 +1731,7 @@ TEST_F(ColumnFamilyTest, SameCFManualAutomaticCompactions) {
        {"ColumnFamilyTest::ManualAuto:1", "ColumnFamilyTest::ManualAuto:2"},
        {"ColumnFamilyTest::ManualAuto:1", "ColumnFamilyTest::ManualAuto:3"}});
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
-      "DBImpl::BackgroundCompaction:NonTrivial:AfterRun", [&](void* /*arg*/) {
+      "DBImpl::BackgroundCompaction:NonTrivial:AfterRun", [&](void* arg) {
         if (cf_1_1) {
           TEST_SYNC_POINT("ColumnFamilyTest::ManualAuto:4");
           cf_1_1 = false;
@@ -1824,7 +1823,7 @@ TEST_F(ColumnFamilyTest, SameCFManualAutomaticCompactionsLevel) {
         "ColumnFamilyTest::ManualAuto:3"},
        {"ColumnFamilyTest::ManualAuto:1", "ColumnFamilyTest::ManualAuto:3"}});
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
-      "DBImpl::BackgroundCompaction:NonTrivial:AfterRun", [&](void* /*arg*/) {
+      "DBImpl::BackgroundCompaction:NonTrivial:AfterRun", [&](void* arg) {
         if (cf_1_1) {
           TEST_SYNC_POINT("ColumnFamilyTest::ManualAuto:4");
           cf_1_1 = false;
@@ -1927,7 +1926,7 @@ TEST_F(ColumnFamilyTest, SameCFManualAutomaticConflict) {
        {"ColumnFamilyTest::ManualAutoCon:1",
         "ColumnFamilyTest::ManualAutoCon:3"}});
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
-      "DBImpl::BackgroundCompaction:NonTrivial:AfterRun", [&](void* /*arg*/) {
+      "DBImpl::BackgroundCompaction:NonTrivial:AfterRun", [&](void* arg) {
         if (cf_1_1) {
           TEST_SYNC_POINT("ColumnFamilyTest::ManualAutoCon:4");
           cf_1_1 = false;
@@ -2031,7 +2030,7 @@ TEST_F(ColumnFamilyTest, SameCFAutomaticManualCompactions) {
        {"CompactionPicker::CompactRange:Conflict",
         "ColumnFamilyTest::AutoManual:3"}});
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
-      "DBImpl::BackgroundCompaction:NonTrivial:AfterRun", [&](void* /*arg*/) {
+      "DBImpl::BackgroundCompaction:NonTrivial:AfterRun", [&](void* arg) {
         if (cf_1_1) {
           TEST_SYNC_POINT("ColumnFamilyTest::AutoManual:4");
           cf_1_1 = false;
@@ -2477,21 +2476,21 @@ TEST_F(ColumnFamilyTest, CreateAndDropRace) {
 
   auto main_thread_id = std::this_thread::get_id();
 
-  rocksdb::SyncPoint::GetInstance()->SetCallBack(
+  rocksdb::SyncPoint::GetInstance()->SetCallBack("PersistRocksDBOptions:start",
-      "PersistRocksDBOptions:start", [&](void* /*arg*/) {
+                                                 [&](void* arg) {
-        auto current_thread_id = std::this_thread::get_id();
+    auto current_thread_id = std::this_thread::get_id();
-        // If it's the main thread hitting this sync-point, then it
+    // If it's the main thread hitting this sync-point, then it
-        // will be blocked until some other thread update the test_stage.
+    // will be blocked until some other thread update the test_stage.
-        if (main_thread_id == current_thread_id) {
+    if (main_thread_id == current_thread_id) {
-          test_stage = kMainThreadStartPersistingOptionsFile;
+      test_stage = kMainThreadStartPersistingOptionsFile;
-          while (test_stage < kChildThreadFinishDroppingColumnFamily) {
+      while (test_stage < kChildThreadFinishDroppingColumnFamily) {
-            Env::Default()->SleepForMicroseconds(100);
+        Env::Default()->SleepForMicroseconds(100);
-          }
+      }
-        }
+    }
-      });
+  });
 
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
-      "WriteThread::EnterUnbatched:Wait", [&](void* /*arg*/) {
+      "WriteThread::EnterUnbatched:Wait", [&](void* arg) {
         // This means a thread doing DropColumnFamily() is waiting for
         // other thread to finish persisting options.
         // In such case, we update the test_stage to unblock the main thread.

db/compact_files_test.cc

@@ -37,7 +37,8 @@ class FlushedFileCollector : public EventListener {
   FlushedFileCollector() {}
   ~FlushedFileCollector() {}
 
-  virtual void OnFlushCompleted(DB* /*db*/, const FlushJobInfo& info) override {
+  virtual void OnFlushCompleted(
+      DB* db, const FlushJobInfo& info) override {
     std::lock_guard<std::mutex> lock(mutex_);
     flushed_files_.push_back(info.file_path);
   }
@@ -256,9 +257,9 @@ TEST_F(CompactFilesTest, CapturingPendingFiles) {
 TEST_F(CompactFilesTest, CompactionFilterWithGetSv) {
   class FilterWithGet : public CompactionFilter {
    public:
-    virtual bool Filter(int /*level*/, const Slice& /*key*/,
+    virtual 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;
       }

db/compacted_db_impl.h

@@ -32,56 +32,55 @@ class CompactedDBImpl : public DBImpl {
     override;
 
   using DBImpl::Put;
-  virtual Status Put(const WriteOptions& /*options*/,
+  virtual Status Put(const WriteOptions& options,
-                     ColumnFamilyHandle* /*column_family*/,
+                     ColumnFamilyHandle* column_family, const Slice& key,
-                     const Slice& /*key*/, const Slice& /*value*/) override {
+                     const Slice& value) override {
     return Status::NotSupported("Not supported in compacted db mode.");
   }
   using DBImpl::Merge;
-  virtual Status Merge(const WriteOptions& /*options*/,
+  virtual Status Merge(const WriteOptions& options,
-                       ColumnFamilyHandle* /*column_family*/,
+                       ColumnFamilyHandle* column_family, const Slice& key,
-                       const Slice& /*key*/, const Slice& /*value*/) override {
+                       const Slice& value) override {
     return Status::NotSupported("Not supported in compacted db mode.");
   }
   using DBImpl::Delete;
-  virtual Status Delete(const WriteOptions& /*options*/,
+  virtual Status Delete(const WriteOptions& options,
-                        ColumnFamilyHandle* /*column_family*/,
+                        ColumnFamilyHandle* column_family,
-                        const Slice& /*key*/) override {
+                        const Slice& key) override {
     return Status::NotSupported("Not supported in compacted db mode.");
   }
-  virtual Status Write(const WriteOptions& /*options*/,
+  virtual Status Write(const WriteOptions& options,
-                       WriteBatch* /*updates*/) override {
+                       WriteBatch* updates) override {
     return Status::NotSupported("Not supported in compacted db mode.");
   }
   using DBImpl::CompactRange;
-  virtual Status CompactRange(const CompactRangeOptions& /*options*/,
+  virtual Status CompactRange(const CompactRangeOptions& options,
-                              ColumnFamilyHandle* /*column_family*/,
+                              ColumnFamilyHandle* column_family,
-                              const Slice* /*begin*/,
+                              const Slice* begin, const Slice* end) override {
-                              const Slice* /*end*/) override {
     return Status::NotSupported("Not supported in compacted db mode.");
   }
 
   virtual Status DisableFileDeletions() override {
     return Status::NotSupported("Not supported in compacted db mode.");
   }
-  virtual Status EnableFileDeletions(bool /*force*/) override {
+  virtual Status EnableFileDeletions(bool force) override {
     return Status::NotSupported("Not supported in compacted db mode.");
   }
   virtual Status GetLiveFiles(std::vector<std::string>&,
-                              uint64_t* /*manifest_file_size*/,
+                              uint64_t* manifest_file_size,
-                              bool /*flush_memtable*/ = true) override {
+                              bool flush_memtable = true) override {
     return Status::NotSupported("Not supported in compacted db mode.");
   }
   using DBImpl::Flush;
-  virtual Status Flush(const FlushOptions& /*options*/,
+  virtual Status Flush(const FlushOptions& options,
-                       ColumnFamilyHandle* /*column_family*/) override {
+                       ColumnFamilyHandle* column_family) override {
     return Status::NotSupported("Not supported in compacted db mode.");
   }
   using DB::IngestExternalFile;
   virtual Status IngestExternalFile(
-      ColumnFamilyHandle* /*column_family*/,
+      ColumnFamilyHandle* column_family,
-      const std::vector<std::string>& /*external_files*/,
+      const std::vector<std::string>& external_files,
-      const IngestExternalFileOptions& /*ingestion_options*/) override {
+      const IngestExternalFileOptions& ingestion_options) override {
     return Status::NotSupported("Not supported in compacted db mode.");
   }
 

db/compaction_iterator.cc

@@ -50,7 +50,7 @@ CompactionIterator::CompactionIterator(
 
 CompactionIterator::CompactionIterator(
     InternalIterator* input, const Comparator* cmp, MergeHelper* merge_helper,
-    SequenceNumber /*last_sequence*/, std::vector<SequenceNumber>* snapshots,
+    SequenceNumber last_sequence, std::vector<SequenceNumber>* snapshots,
     SequenceNumber earliest_write_conflict_snapshot, Env* env,
     bool expect_valid_internal_key, RangeDelAggregator* range_del_agg,
     std::unique_ptr<CompactionProxy> compaction,

db/compaction_iterator.h

@@ -31,7 +31,7 @@ class CompactionIterator {
         : compaction_(compaction) {}
 
     virtual ~CompactionProxy() = default;
-    virtual int level(size_t /*compaction_input_level*/ = 0) const {
+    virtual int level(size_t compaction_input_level = 0) const {
       return compaction_->level();
     }
     virtual bool KeyNotExistsBeyondOutputLevel(

db/compaction_iterator_test.cc

@@ -17,15 +17,15 @@ namespace rocksdb {
 // Expects no merging attempts.
 class NoMergingMergeOp : public MergeOperator {
  public:
-  bool FullMergeV2(const MergeOperationInput& /*merge_in*/,
+  bool FullMergeV2(const MergeOperationInput& merge_in,
-                   MergeOperationOutput* /*merge_out*/) const override {
+                   MergeOperationOutput* merge_out) const override {
     ADD_FAILURE();
     return false;
   }
-  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 {
     ADD_FAILURE();
     return false;
   }
@@ -39,10 +39,9 @@ class NoMergingMergeOp : public MergeOperator {
 // Always returns Decition::kRemove.
 class StallingFilter : public CompactionFilter {
  public:
-  virtual Decision FilterV2(int /*level*/, const Slice& key, ValueType /*t*/,
+  virtual 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 {
     int k = std::atoi(key.ToString().c_str());
     last_seen.store(k);
     while (k >= stall_at.load()) {
@@ -113,7 +112,7 @@ class LoggingForwardVectorIterator : public InternalIterator {
                keys_.begin();
   }
 
-  virtual void SeekForPrev(const Slice& /*target*/) override { assert(false); }
+  virtual void SeekForPrev(const Slice& target) override { assert(false); }
 
   virtual void Next() override {
     assert(Valid());
@@ -145,9 +144,9 @@ class FakeCompaction : public CompactionIterator::CompactionProxy {
  public:
   FakeCompaction() = default;
 
-  virtual int level(size_t /*compaction_input_level*/) const { return 0; }
+  virtual int level(size_t compaction_input_level) const { return 0; }
   virtual bool KeyNotExistsBeyondOutputLevel(
-      const Slice& /*user_key*/, std::vector<size_t>* /*level_ptrs*/) const {
+      const Slice& user_key, std::vector<size_t>* level_ptrs) const {
     return key_not_exists_beyond_output_level;
   }
   virtual bool bottommost_level() const { return false; }
@@ -277,9 +276,9 @@ TEST_F(CompactionIteratorTest, RangeDeletionWithSnapshots) {
 
 TEST_F(CompactionIteratorTest, CompactionFilterSkipUntil) {
   class Filter : public CompactionFilter {
-    virtual Decision FilterV2(int /*level*/, const Slice& key, ValueType t,
+    virtual Decision FilterV2(int level, const Slice& key, ValueType t,
                               const Slice& existing_value,
-                              std::string* /*new_value*/,
+                              std::string* new_value,
                               std::string* skip_until) const override {
       std::string k = key.ToString();
       std::string v = existing_value.ToString();

db/compaction_job_stats_test.cc

@@ -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) {
+  virtual void OnCompactionCompleted(DB *db, const CompactionJobInfo& ci) {
     if (verify_next_comp_io_stats_) {
       ASSERT_GT(ci.stats.file_write_nanos, 0);
       ASSERT_GT(ci.stats.file_range_sync_nanos, 0);
@@ -806,7 +806,7 @@ TEST_P(CompactionJobStatsTest, CompactionJobStatsTest) {
     stats_checker->set_verify_next_comp_io_stats(true);
     std::atomic<bool> first_prepare_write(true);
     rocksdb::SyncPoint::GetInstance()->SetCallBack(
-        "WritableFileWriter::Append:BeforePrepareWrite", [&](void* /*arg*/) {
+        "WritableFileWriter::Append:BeforePrepareWrite", [&](void* arg) {
           if (first_prepare_write.load()) {
             options.env->SleepForMicroseconds(3);
             first_prepare_write.store(false);
@@ -815,7 +815,7 @@ TEST_P(CompactionJobStatsTest, CompactionJobStatsTest) {
 
     std::atomic<bool> first_flush(true);
     rocksdb::SyncPoint::GetInstance()->SetCallBack(
-        "WritableFileWriter::Flush:BeforeAppend", [&](void* /*arg*/) {
+        "WritableFileWriter::Flush:BeforeAppend", [&](void* arg) {
           if (first_flush.load()) {
             options.env->SleepForMicroseconds(3);
             first_flush.store(false);
@@ -824,7 +824,7 @@ TEST_P(CompactionJobStatsTest, CompactionJobStatsTest) {
 
     std::atomic<bool> first_sync(true);
     rocksdb::SyncPoint::GetInstance()->SetCallBack(
-        "WritableFileWriter::SyncInternal:0", [&](void* /*arg*/) {
+        "WritableFileWriter::SyncInternal:0", [&](void* arg) {
           if (first_sync.load()) {
             options.env->SleepForMicroseconds(3);
             first_sync.store(false);
@@ -833,7 +833,7 @@ TEST_P(CompactionJobStatsTest, CompactionJobStatsTest) {
 
     std::atomic<bool> first_range_sync(true);
     rocksdb::SyncPoint::GetInstance()->SetCallBack(
-        "WritableFileWriter::RangeSync:0", [&](void* /*arg*/) {
+        "WritableFileWriter::RangeSync:0", [&](void* arg) {
           if (first_range_sync.load()) {
             options.env->SleepForMicroseconds(3);
             first_range_sync.store(false);

db/compaction_picker.cc

@@ -199,7 +199,7 @@ void CompactionPicker::GetRange(const std::vector<CompactionInputFiles>& inputs,
   assert(initialized);
 }
 
-bool CompactionPicker::ExpandInputsToCleanCut(const std::string& /*cf_name*/,
+bool CompactionPicker::ExpandInputsToCleanCut(const std::string& cf_name,
                                               VersionStorageInfo* vstorage,
                                               CompactionInputFiles* inputs) {
   // This isn't good compaction
@@ -318,7 +318,7 @@ Compaction* CompactionPicker::CompactFiles(
 Status CompactionPicker::GetCompactionInputsFromFileNumbers(
     std::vector<CompactionInputFiles>* input_files,
     std::unordered_set<uint64_t>* input_set, const VersionStorageInfo* vstorage,
-    const CompactionOptions& /*compact_options*/) const {
+    const CompactionOptions& compact_options) const {
   if (input_set->size() == 0U) {
     return Status::InvalidArgument(
         "Compaction must include at least one file.");
@@ -1581,9 +1581,8 @@ Compaction* FIFOCompactionPicker::PickCompaction(
 Compaction* FIFOCompactionPicker::CompactRange(
     const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
     VersionStorageInfo* vstorage, int input_level, int output_level,
-    uint32_t /*output_path_id*/, const InternalKey* /*begin*/,
+    uint32_t output_path_id, const InternalKey* begin, const InternalKey* end,
-    const InternalKey* /*end*/, InternalKey** compaction_end,
+    InternalKey** compaction_end, bool* manual_conflict) {
-    bool* /*manual_conflict*/) {
   assert(input_level == 0);
   assert(output_level == 0);
   *compaction_end = nullptr;

db/compaction_picker.h

@@ -263,29 +263,27 @@ class NullCompactionPicker : public CompactionPicker {
   virtual ~NullCompactionPicker() {}
 
   // Always return "nullptr"
-  Compaction* PickCompaction(const std::string& /*cf_name*/,
+  Compaction* PickCompaction(const std::string& cf_name,
-                             const MutableCFOptions& /*mutable_cf_options*/,
+                             const MutableCFOptions& mutable_cf_options,
-                             VersionStorageInfo* /*vstorage*/,
+                             VersionStorageInfo* vstorage,
-                             LogBuffer* /*log_buffer*/) override {
+                             LogBuffer* log_buffer) override {
     return nullptr;
   }
 
   // Always return "nullptr"
-  Compaction* CompactRange(const std::string& /*cf_name*/,
+  Compaction* CompactRange(const std::string& cf_name,
-                           const MutableCFOptions& /*mutable_cf_options*/,
+                           const MutableCFOptions& mutable_cf_options,
-                           VersionStorageInfo* /*vstorage*/,
+                           VersionStorageInfo* vstorage, int input_level,
-                           int /*input_level*/, int /*output_level*/,
+                           int output_level, uint32_t output_path_id,
-                           uint32_t /*output_path_id*/,
+                           const InternalKey* begin, const InternalKey* end,
-                           const InternalKey* /*begin*/,
+                           InternalKey** compaction_end,
-                           const InternalKey* /*end*/,
+                           bool* manual_conflict) override {
-                           InternalKey** /*compaction_end*/,
-                           bool* /*manual_conflict*/) override {
     return nullptr;
   }
 
   // Always returns false.
   virtual bool NeedsCompaction(
-      const VersionStorageInfo* /*vstorage*/) const override {
+      const VersionStorageInfo* vstorage) const override {
     return false;
   }
 };

db/compaction_picker_test.cc

@@ -20,9 +20,7 @@ namespace rocksdb {
 class CountingLogger : public Logger {
  public:
   using Logger::Logv;
-  virtual void Logv(const char* /*format*/, va_list /*ap*/) override {
+  virtual void Logv(const char* format, va_list ap) override { log_count++; }
-    log_count++;
-  }
   size_t log_count;
 };
 

db/comparator_db_test.cc

@@ -188,10 +188,10 @@ class DoubleComparator : public Comparator {
       return -1;
     }
   }
-  virtual void FindShortestSeparator(std::string* /*start*/,
+  virtual void FindShortestSeparator(std::string* start,
-                                     const Slice& /*limit*/) const override {}
+                                     const Slice& limit) const override {}
 
-  virtual void FindShortSuccessor(std::string* /*key*/) const override {}
+  virtual void FindShortSuccessor(std::string* key) const override {}
 };
 
 class HashComparator : public Comparator {
@@ -211,10 +211,10 @@ class HashComparator : public Comparator {
       return -1;
     }
   }
-  virtual void FindShortestSeparator(std::string* /*start*/,
+  virtual void FindShortestSeparator(std::string* start,
-                                     const Slice& /*limit*/) const override {}
+                                     const Slice& limit) const override {}
 
-  virtual void FindShortSuccessor(std::string* /*key*/) const override {}
+  virtual void FindShortSuccessor(std::string* key) const override {}
 };
 
 class TwoStrComparator : public Comparator {
@@ -243,10 +243,10 @@ class TwoStrComparator : public Comparator {
     }
     return a2.compare(b2);
   }
-  virtual void FindShortestSeparator(std::string* /*start*/,
+  virtual void FindShortestSeparator(std::string* start,
-                                     const Slice& /*limit*/) const override {}
+                                     const Slice& limit) const override {}
 
-  virtual void FindShortSuccessor(std::string* /*key*/) const override {}
+  virtual void FindShortSuccessor(std::string* key) const override {}
 };
 }  // namespace
 

db/db_block_cache_test.cc

@@ -47,7 +47,7 @@ class DBBlockCacheTest : public DBTestBase {
     return options;
   }
 
-  void InitTable(const Options& /*options*/) {
+  void InitTable(const Options& options) {
     std::string value(kValueSize, 'a');
     for (size_t i = 0; i < kNumBlocks; i++) {
       ASSERT_OK(Put(ToString(i), value.c_str()));

db/db_bloom_filter_test.cc

@@ -1057,10 +1057,10 @@ TEST_F(DBBloomFilterTest, OptimizeFiltersForHits) {
   int32_t non_trivial_move = 0;
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:TrivialMove",
-      [&](void* /*arg*/) { trivial_move++; });
+      [&](void* arg) { trivial_move++; });
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:NonTrivial",
-      [&](void* /*arg*/) { non_trivial_move++; });
+      [&](void* arg) { non_trivial_move++; });
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();
 
   CompactRangeOptions compact_options;

db/db_compaction_filter_test.cc

@@ -26,9 +26,9 @@ class DBTestCompactionFilter : public DBTestBase {
 
 class KeepFilter : public CompactionFilter {
  public:
-  virtual bool Filter(int /*level*/, const Slice& /*key*/,
+  virtual 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
-                      bool* /*value_changed*/) const override {
+      override {
     cfilter_count++;
     return false;
   }
@@ -38,9 +38,9 @@ class KeepFilter : public CompactionFilter {
 
 class DeleteFilter : public CompactionFilter {
  public:
-  virtual bool Filter(int /*level*/, const Slice& /*key*/,
+  virtual 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
-                      bool* /*value_changed*/) const override {
+      override {
     cfilter_count++;
     return true;
   }
@@ -50,9 +50,9 @@ class DeleteFilter : public CompactionFilter {
 
 class DeleteISFilter : public CompactionFilter {
  public:
-  virtual bool Filter(int /*level*/, const Slice& key, const Slice& /*value*/,
+  virtual 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) {
@@ -70,10 +70,8 @@ class DeleteISFilter : public CompactionFilter {
 // zero-padded to length 10.
 class SkipEvenFilter : public CompactionFilter {
  public:
-  virtual Decision FilterV2(int /*level*/, const Slice& key,
+  virtual 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* /*new_value*/,
                             std::string* skip_until) const override {
     cfilter_count++;
     int i = std::stoi(key.ToString());
@@ -95,9 +93,9 @@ class SkipEvenFilter : public CompactionFilter {
 class DelayFilter : public CompactionFilter {
  public:
   explicit DelayFilter(DBTestBase* d) : db_test(d) {}
-  virtual bool Filter(int /*level*/, const Slice& /*key*/,
+  virtual 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;
   }
@@ -112,9 +110,9 @@ 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,
+  virtual 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_;
   }
 
@@ -128,9 +126,9 @@ class ChangeFilter : public CompactionFilter {
  public:
   explicit ChangeFilter() {}
 
-  virtual bool Filter(int /*level*/, const Slice& /*key*/,
+  virtual 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
-                      bool* value_changed) const override {
+      override {
     assert(new_value != nullptr);
     *new_value = NEW_VALUE;
     *value_changed = true;
@@ -219,7 +217,7 @@ class DelayFilterFactory : public CompactionFilterFactory {
  public:
   explicit DelayFilterFactory(DBTestBase* d) : db_test(d) {}
   virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
-      const CompactionFilter::Context& /*context*/) override {
+      const CompactionFilter::Context& context) override {
     return std::unique_ptr<CompactionFilter>(new DelayFilter(db_test));
   }
 
@@ -235,7 +233,7 @@ class ConditionalFilterFactory : public CompactionFilterFactory {
       : filtered_value_(filtered_value.ToString()) {}
 
   virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
-      const CompactionFilter::Context& /*context*/) override {
+      const CompactionFilter::Context& context) override {
     return std::unique_ptr<CompactionFilter>(
         new ConditionalFilter(&filtered_value_));
   }
@@ -253,7 +251,7 @@ class ChangeFilterFactory : public CompactionFilterFactory {
   explicit ChangeFilterFactory() {}
 
   virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
-      const CompactionFilter::Context& /*context*/) override {
+      const CompactionFilter::Context& context) override {
     return std::unique_ptr<CompactionFilter>(new ChangeFilter());
   }
 

db/db_compaction_test.cc

@@ -53,7 +53,7 @@ class FlushedFileCollector : public EventListener {
   FlushedFileCollector() {}
   ~FlushedFileCollector() {}
 
-  virtual void OnFlushCompleted(DB* /*db*/, const FlushJobInfo& info) override {
+  virtual void OnFlushCompleted(DB* db, const FlushJobInfo& info) override {
     std::lock_guard<std::mutex> lock(mutex_);
     flushed_files_.push_back(info.file_path);
   }
@@ -282,7 +282,7 @@ TEST_F(DBCompactionTest, TestTableReaderForCompaction) {
       });
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "TableCache::GetTableReader:0",
-      [&](void* /*arg*/) { num_new_table_reader++; });
+      [&](void* arg) { num_new_table_reader++; });
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();
 
   for (int k = 0; k < options.level0_file_num_compaction_trigger; ++k) {
@@ -838,7 +838,7 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveOneFile) {
   int32_t trivial_move = 0;
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:TrivialMove",
-      [&](void* /*arg*/) { trivial_move++; });
+      [&](void* arg) { trivial_move++; });
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();
 
   Options options = CurrentOptions();
@@ -895,10 +895,10 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveNonOverlappingFiles) {
   int32_t non_trivial_move = 0;
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:TrivialMove",
-      [&](void* /*arg*/) { trivial_move++; });
+      [&](void* arg) { trivial_move++; });
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:NonTrivial",
-      [&](void* /*arg*/) { non_trivial_move++; });
+      [&](void* arg) { non_trivial_move++; });
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();
 
   Options options = CurrentOptions();
@@ -994,10 +994,10 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveTargetLevel) {
   int32_t non_trivial_move = 0;
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:TrivialMove",
-      [&](void* /*arg*/) { trivial_move++; });
+      [&](void* arg) { trivial_move++; });
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:NonTrivial",
-      [&](void* /*arg*/) { non_trivial_move++; });
+      [&](void* arg) { non_trivial_move++; });
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();
 
   Options options = CurrentOptions();
@@ -1053,10 +1053,10 @@ TEST_P(DBCompactionTestWithParam, ManualCompactionPartial) {
   int32_t non_trivial_move = 0;
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:TrivialMove",
-      [&](void* /*arg*/) { trivial_move++; });
+      [&](void* arg) { trivial_move++; });
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:NonTrivial",
-      [&](void* /*arg*/) { non_trivial_move++; });
+      [&](void* arg) { non_trivial_move++; });
   bool first = true;
   // Purpose of dependencies:
   // 4 -> 1: ensure the order of two non-trivial compactions
@@ -1067,7 +1067,7 @@ TEST_P(DBCompactionTestWithParam, ManualCompactionPartial) {
        {"DBCompaction::ManualPartial:5", "DBCompaction::ManualPartial:2"},
        {"DBCompaction::ManualPartial:5", "DBCompaction::ManualPartial:3"}});
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
-      "DBImpl::BackgroundCompaction:NonTrivial:AfterRun", [&](void* /*arg*/) {
+      "DBImpl::BackgroundCompaction:NonTrivial:AfterRun", [&](void* arg) {
         if (first) {
           first = false;
           TEST_SYNC_POINT("DBCompaction::ManualPartial:4");
@@ -1198,17 +1198,17 @@ TEST_F(DBCompactionTest, DISABLED_ManualPartialFill) {
   int32_t non_trivial_move = 0;
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:TrivialMove",
-      [&](void* /*arg*/) { trivial_move++; });
+      [&](void* arg) { trivial_move++; });
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:NonTrivial",
-      [&](void* /*arg*/) { non_trivial_move++; });
+      [&](void* arg) { non_trivial_move++; });
   bool first = true;
   bool second = true;
   rocksdb::SyncPoint::GetInstance()->LoadDependency(
       {{"DBCompaction::PartialFill:4", "DBCompaction::PartialFill:1"},
        {"DBCompaction::PartialFill:2", "DBCompaction::PartialFill:3"}});
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
-      "DBImpl::BackgroundCompaction:NonTrivial:AfterRun", [&](void* /*arg*/) {
+      "DBImpl::BackgroundCompaction:NonTrivial:AfterRun", [&](void* arg) {
         if (first) {
           TEST_SYNC_POINT("DBCompaction::PartialFill:4");
           first = false;
@@ -1444,10 +1444,10 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveToLastLevelWithFiles) {
   int32_t non_trivial_move = 0;
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:TrivialMove",
-      [&](void* /*arg*/) { trivial_move++; });
+      [&](void* arg) { trivial_move++; });
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:NonTrivial",
-      [&](void* /*arg*/) { non_trivial_move++; });
+      [&](void* arg) { non_trivial_move++; });
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();
 
   Options options = CurrentOptions();
@@ -2325,16 +2325,16 @@ TEST_P(DBCompactionTestWithParam, CompressLevelCompaction) {
 
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "Compaction::InputCompressionMatchesOutput:Matches",
-      [&](void* /*arg*/) { matches++; });
+      [&](void* arg) { matches++; });
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "Compaction::InputCompressionMatchesOutput:DidntMatch",
-      [&](void* /*arg*/) { didnt_match++; });
+      [&](void* arg) { didnt_match++; });
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:NonTrivial",
-      [&](void* /*arg*/) { non_trivial++; });
+      [&](void* arg) { non_trivial++; });
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:TrivialMove",
-      [&](void* /*arg*/) { trivial_move++; });
+      [&](void* arg) { trivial_move++; });
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();
 
   Reopen(options);
@@ -2496,10 +2496,10 @@ TEST_P(DBCompactionTestWithParam, ForceBottommostLevelCompaction) {
   int32_t non_trivial_move = 0;
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:TrivialMove",
-      [&](void* /*arg*/) { trivial_move++; });
+      [&](void* arg) { trivial_move++; });
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:NonTrivial",
-      [&](void* /*arg*/) { non_trivial_move++; });
+      [&](void* arg) { non_trivial_move++; });
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();
 
   Options options = CurrentOptions();
@@ -2656,7 +2656,9 @@ TEST_P(DBCompactionDirectIOTest, DirectIO) {
       });
   if (options.use_direct_io_for_flush_and_compaction) {
     SyncPoint::GetInstance()->SetCallBack(
-        "SanitizeOptions:direct_io", [&](void* /*arg*/) { readahead = true; });
+        "SanitizeOptions:direct_io", [&](void* arg) {
+          readahead = true;
+        });
   }
   SyncPoint::GetInstance()->EnableProcessing();
   CreateAndReopenWithCF({"pikachu"}, options);

db/db_dynamic_level_test.cc

@@ -194,7 +194,7 @@ TEST_F(DBTestDynamicLevel, DynamicLevelMaxBytesBase2) {
   // Hold compaction jobs to make sure
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "CompactionJob::Run():Start",
-      [&](void* /*arg*/) { env_->SleepForMicroseconds(100000); });
+      [&](void* arg) { env_->SleepForMicroseconds(100000); });
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();
   ASSERT_OK(dbfull()->SetOptions({
       {"disable_auto_compactions", "true"},
@@ -378,7 +378,7 @@ TEST_F(DBTestDynamicLevel, DynamicLevelMaxBytesBaseInc) {
   int non_trivial = 0;
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:NonTrivial",
-      [&](void* /*arg*/) { non_trivial++; });
+      [&](void* arg) { non_trivial++; });
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();
 
   Random rnd(301);

db/db_flush_test.cc

@@ -101,7 +101,7 @@ TEST_F(DBFlushTest, FlushInLowPriThreadPool) {
   std::thread::id tid;
   int num_flushes = 0, num_compactions = 0;
   SyncPoint::GetInstance()->SetCallBack(
-      "DBImpl::BGWorkFlush", [&](void* /*arg*/) {
+      "DBImpl::BGWorkFlush", [&](void* arg) {
         if (tid == std::thread::id()) {
           tid = std::this_thread::get_id();
         } else {
@@ -110,7 +110,7 @@ TEST_F(DBFlushTest, FlushInLowPriThreadPool) {
         ++num_flushes;
       });
   SyncPoint::GetInstance()->SetCallBack(
-      "DBImpl::BGWorkCompaction", [&](void* /*arg*/) {
+      "DBImpl::BGWorkCompaction", [&](void* arg) {
         ASSERT_EQ(tid, std::this_thread::get_id());
         ++num_compactions;
       });

db/db_impl.cc

@@ -595,9 +595,8 @@ Status DBImpl::SetDBOptions(
 }
 
 // return the same level if it cannot be moved
-int DBImpl::FindMinimumEmptyLevelFitting(
+int DBImpl::FindMinimumEmptyLevelFitting(ColumnFamilyData* cfd,
-    ColumnFamilyData* cfd, const MutableCFOptions& /*mutable_cf_options*/,
+    const MutableCFOptions& mutable_cf_options, int level) {
-    int level) {
   mutex_.AssertHeld();
   const auto* vstorage = cfd->current()->storage_info();
   int minimum_level = level;
@@ -807,7 +806,7 @@ struct IterState {
   bool background_purge;
 };
 
-static void CleanupIteratorState(void* arg1, void* /*arg2*/) {
+static void CleanupIteratorState(void* arg1, void* arg2) {
   IterState* state = reinterpret_cast<IterState*>(arg1);
 
   if (state->super_version->Unref()) {
@@ -2191,31 +2190,31 @@ Status DBImpl::GetDbIdentity(std::string& identity) const {
 }
 
 // Default implementation -- returns not supported status
-Status DB::CreateColumnFamily(const ColumnFamilyOptions& /*cf_options*/,
+Status DB::CreateColumnFamily(const ColumnFamilyOptions& cf_options,
-                              const std::string& /*column_family_name*/,
+                              const std::string& column_family_name,
-                              ColumnFamilyHandle** /*handle*/) {
+                              ColumnFamilyHandle** handle) {
   return Status::NotSupported("");
 }
 
 Status DB::CreateColumnFamilies(
-    const ColumnFamilyOptions& /*cf_options*/,
+    const ColumnFamilyOptions& cf_options,
-    const std::vector<std::string>& /*column_family_names*/,
+    const std::vector<std::string>& column_family_names,
-    std::vector<ColumnFamilyHandle*>* /*handles*/) {
+    std::vector<ColumnFamilyHandle*>* handles) {
   return Status::NotSupported("");
 }
 
 Status DB::CreateColumnFamilies(
-    const std::vector<ColumnFamilyDescriptor>& /*column_families*/,
+    const std::vector<ColumnFamilyDescriptor>& column_families,
-    std::vector<ColumnFamilyHandle*>* /*handles*/) {
+    std::vector<ColumnFamilyHandle*>* handles) {
   return Status::NotSupported("");
 }
 
-Status DB::DropColumnFamily(ColumnFamilyHandle* /*column_family*/) {
+Status DB::DropColumnFamily(ColumnFamilyHandle* column_family) {
   return Status::NotSupported("");
 }
 
 Status DB::DropColumnFamilies(
-    const std::vector<ColumnFamilyHandle*>& /*column_families*/) {
+    const std::vector<ColumnFamilyHandle*>& column_families) {
   return Status::NotSupported("");
 }
 

db/db_impl_compaction_flush.cc

@@ -779,7 +779,7 @@ int DBImpl::NumberLevels(ColumnFamilyHandle* column_family) {
   return cfh->cfd()->NumberLevels();
 }
 
-int DBImpl::MaxMemCompactionLevel(ColumnFamilyHandle* /*column_family*/) {
+int DBImpl::MaxMemCompactionLevel(ColumnFamilyHandle* column_family) {
   return 0;
 }
 

db/db_impl_readonly.cc

@@ -105,7 +105,7 @@ Status DBImplReadOnly::NewIterators(
 }
 
 Status DB::OpenForReadOnly(const Options& options, const std::string& dbname,
-                           DB** dbptr, bool /*error_if_log_file_exist*/) {
+                           DB** dbptr, bool error_if_log_file_exist) {
   *dbptr = nullptr;
 
   // Try to first open DB as fully compacted DB

db/db_impl_readonly.h

@@ -36,47 +36,46 @@ class DBImplReadOnly : public DBImpl {
       std::vector<Iterator*>* iterators) override;
 
   using DBImpl::Put;
-  virtual Status Put(const WriteOptions& /*options*/,
+  virtual Status Put(const WriteOptions& options,
-                     ColumnFamilyHandle* /*column_family*/,
+                     ColumnFamilyHandle* column_family, const Slice& key,
-                     const Slice& /*key*/, const Slice& /*value*/) override {
+                     const Slice& value) override {
     return Status::NotSupported("Not supported operation in read only mode.");
   }
   using DBImpl::Merge;
-  virtual Status Merge(const WriteOptions& /*options*/,
+  virtual Status Merge(const WriteOptions& options,
-                       ColumnFamilyHandle* /*column_family*/,
+                       ColumnFamilyHandle* column_family, const Slice& key,
-                       const Slice& /*key*/, const Slice& /*value*/) override {
+                       const Slice& value) override {
     return Status::NotSupported("Not supported operation in read only mode.");
   }
   using DBImpl::Delete;
-  virtual Status Delete(const WriteOptions& /*options*/,
+  virtual Status Delete(const WriteOptions& options,
-                        ColumnFamilyHandle* /*column_family*/,
+                        ColumnFamilyHandle* column_family,
-                        const Slice& /*key*/) override {
+                        const Slice& key) override {
     return Status::NotSupported("Not supported operation in read only mode.");
   }
   using DBImpl::SingleDelete;
-  virtual Status SingleDelete(const WriteOptions& /*options*/,
+  virtual Status SingleDelete(const WriteOptions& options,
-                              ColumnFamilyHandle* /*column_family*/,
+                              ColumnFamilyHandle* column_family,
-                              const Slice& /*key*/) override {
+                              const Slice& key) override {
     return Status::NotSupported("Not supported operation in read only mode.");
   }
-  virtual Status Write(const WriteOptions& /*options*/,
+  virtual Status Write(const WriteOptions& options,
-                       WriteBatch* /*updates*/) override {
+                       WriteBatch* updates) override {
     return Status::NotSupported("Not supported operation in read only mode.");
   }
   using DBImpl::CompactRange;
-  virtual Status CompactRange(const CompactRangeOptions& /*options*/,
+  virtual Status CompactRange(const CompactRangeOptions& options,
-                              ColumnFamilyHandle* /*column_family*/,
+                              ColumnFamilyHandle* column_family,
-                              const Slice* /*begin*/,
+                              const Slice* begin, const Slice* end) override {
-                              const Slice* /*end*/) override {
     return Status::NotSupported("Not supported operation in read only mode.");
   }
 
   using DBImpl::CompactFiles;
   virtual Status CompactFiles(
-      const CompactionOptions& /*compact_options*/,
+      const CompactionOptions& compact_options,
-      ColumnFamilyHandle* /*column_family*/,
+      ColumnFamilyHandle* column_family,
-      const std::vector<std::string>& /*input_file_names*/,
+      const std::vector<std::string>& input_file_names,
-      const int /*output_level*/, const int /*output_path_id*/ = -1) override {
+      const int output_level, const int output_path_id = -1) override {
     return Status::NotSupported("Not supported operation in read only mode.");
   }
 
@@ -84,18 +83,18 @@ class DBImplReadOnly : public DBImpl {
     return Status::NotSupported("Not supported operation in read only mode.");
   }
 
-  virtual Status EnableFileDeletions(bool /*force*/) override {
+  virtual Status EnableFileDeletions(bool force) override {
     return Status::NotSupported("Not supported operation in read only mode.");
   }
   virtual Status GetLiveFiles(std::vector<std::string>&,
-                              uint64_t* /*manifest_file_size*/,
+                              uint64_t* manifest_file_size,
-                              bool /*flush_memtable*/ = true) override {
+                              bool flush_memtable = true) override {
     return Status::NotSupported("Not supported operation in read only mode.");
   }
 
   using DBImpl::Flush;
-  virtual Status Flush(const FlushOptions& /*options*/,
+  virtual Status Flush(const FlushOptions& options,
-                       ColumnFamilyHandle* /*column_family*/) override {
+                       ColumnFamilyHandle* column_family) override {
     return Status::NotSupported("Not supported operation in read only mode.");
   }
 
@@ -106,9 +105,9 @@ class DBImplReadOnly : public DBImpl {
 
   using DB::IngestExternalFile;
   virtual Status IngestExternalFile(
-      ColumnFamilyHandle* /*column_family*/,
+      ColumnFamilyHandle* column_family,
-      const std::vector<std::string>& /*external_files*/,
+      const std::vector<std::string>& external_files,
-      const IngestExternalFileOptions& /*ingestion_options*/) override {
+      const IngestExternalFileOptions& ingestion_options) override {
     return Status::NotSupported("Not supported operation in read only mode.");
   }
 

db/db_impl_write.cc

@@ -1002,7 +1002,7 @@ Status DBImpl::ScheduleFlushes(WriteContext* context) {
 }
 
 #ifndef ROCKSDB_LITE
-void DBImpl::NotifyOnMemTableSealed(ColumnFamilyData* /*cfd*/,
+void DBImpl::NotifyOnMemTableSealed(ColumnFamilyData* cfd,
                                     const MemTableInfo& mem_table_info) {
   if (immutable_db_options_.listeners.size() == 0U) {
     return;

db/db_iter_test.cc

@@ -2459,7 +2459,7 @@ TEST_F(DBIterWithMergeIterTest, InnerMergeIteratorDataRace1) {
   // and before an SeekToLast() is called.
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "MergeIterator::Prev:BeforeSeekToLast",
-      [&](void* /*arg*/) { internal_iter2_->Add("z", kTypeValue, "7", 12u); });
+      [&](void* arg) { internal_iter2_->Add("z", kTypeValue, "7", 12u); });
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();
 
   db_iter_->Prev();
@@ -2494,7 +2494,7 @@ TEST_F(DBIterWithMergeIterTest, InnerMergeIteratorDataRace2) {
   // mem table after MergeIterator::Prev() realized the mem tableiterator is at
   // its end and before an SeekToLast() is called.
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
-      "MergeIterator::Prev:BeforeSeekToLast", [&](void* /*arg*/) {
+      "MergeIterator::Prev:BeforeSeekToLast", [&](void* arg) {
         internal_iter2_->Add("z", kTypeValue, "7", 12u);
         internal_iter2_->Add("z", kTypeValue, "7", 11u);
       });
@@ -2532,7 +2532,7 @@ TEST_F(DBIterWithMergeIterTest, InnerMergeIteratorDataRace3) {
   // mem table after MergeIterator::Prev() realized the mem table iterator is at
   // its end and before an SeekToLast() is called.
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
-      "MergeIterator::Prev:BeforeSeekToLast", [&](void* /*arg*/) {
+      "MergeIterator::Prev:BeforeSeekToLast", [&](void* arg) {
         internal_iter2_->Add("z", kTypeValue, "7", 16u, true);
         internal_iter2_->Add("z", kTypeValue, "7", 15u, true);
         internal_iter2_->Add("z", kTypeValue, "7", 14u, true);

db/db_iterator_test.cc

@@ -24,7 +24,7 @@ class DBIteratorTest : public DBTestBase {
 
 class FlushBlockEveryKeyPolicy : public FlushBlockPolicy {
  public:
-  virtual bool Update(const Slice& /*key*/, const Slice& /*value*/) override {
+  virtual bool Update(const Slice& key, const Slice& value) override {
     if (!start_) {
       start_ = true;
       return false;
@@ -44,8 +44,8 @@ class FlushBlockEveryKeyPolicyFactory : public FlushBlockPolicyFactory {
   }
 
   FlushBlockPolicy* NewFlushBlockPolicy(
-      const BlockBasedTableOptions& /*table_options*/,
+    const BlockBasedTableOptions& table_options,
-      const BlockBuilder& /*data_block_builder*/) const override {
+    const BlockBuilder& data_block_builder) const override {
     return new FlushBlockEveryKeyPolicy;
   }
 };

db/db_memtable_test.cc

@@ -121,7 +121,7 @@ class TestPrefixExtractor : public SliceTransform {
     return separator(key) != nullptr;
   }
 
-  virtual bool InRange(const Slice& /*key*/) const override { return false; }
+  virtual bool InRange(const Slice& key) const override { return false; }
 
  private:
   const char* separator(const Slice& key) const {

db/db_properties_test.cc

@@ -985,9 +985,8 @@ class CountingUserTblPropCollector : public TablePropertiesCollector {
     return Status::OK();
   }
 
-  Status AddUserKey(const Slice& /*user_key*/, const Slice& /*value*/,
+  Status AddUserKey(const Slice& user_key, const Slice& value, EntryType type,
-                    EntryType /*type*/, SequenceNumber /*seq*/,
+                    SequenceNumber seq, uint64_t file_size) override {
-                    uint64_t /*file_size*/) override {
     ++count_;
     return Status::OK();
   }
@@ -1028,9 +1027,8 @@ class CountingDeleteTabPropCollector : public TablePropertiesCollector {
  public:
   const char* Name() const override { return "CountingDeleteTabPropCollector"; }
 
-  Status AddUserKey(const Slice& /*user_key*/, const Slice& /*value*/,
+  Status AddUserKey(const Slice& user_key, const Slice& value, EntryType type,
-                    EntryType type, SequenceNumber /*seq*/,
+                    SequenceNumber seq, uint64_t file_size) override {
-                    uint64_t /*file_size*/) override {
     if (type == kEntryDelete) {
       num_deletes_++;
     }
@@ -1057,7 +1055,7 @@ class CountingDeleteTabPropCollectorFactory
     : public TablePropertiesCollectorFactory {
  public:
   virtual TablePropertiesCollector* CreateTablePropertiesCollector(
-      TablePropertiesCollectorFactory::Context /*context*/) override {
+      TablePropertiesCollectorFactory::Context context) override {
     return new CountingDeleteTabPropCollector();
   }
   const char* Name() const override {

db/db_sst_test.cc

@@ -231,12 +231,11 @@ TEST_F(DBSSTTest, DBWithSstFileManager) {
   int files_deleted = 0;
   int files_moved = 0;
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
-      "SstFileManagerImpl::OnAddFile", [&](void* /*arg*/) { files_added++; });
+      "SstFileManagerImpl::OnAddFile", [&](void* arg) { files_added++; });
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
-      "SstFileManagerImpl::OnDeleteFile",
+      "SstFileManagerImpl::OnDeleteFile", [&](void* arg) { files_deleted++; });
-      [&](void* /*arg*/) { files_deleted++; });
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
-      "SstFileManagerImpl::OnMoveFile", [&](void* /*arg*/) { files_moved++; });
+      "SstFileManagerImpl::OnMoveFile", [&](void* arg) { files_moved++; });
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();
 
   Options options = CurrentOptions();
@@ -386,7 +385,7 @@ TEST_F(DBSSTTest, DeleteSchedulerMultipleDBPaths) {
   int bg_delete_file = 0;
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DeleteScheduler::DeleteTrashFile:DeleteFile",
-      [&](void* /*arg*/) { bg_delete_file++; });
+      [&](void* arg) { bg_delete_file++; });
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();
 
   Options options = CurrentOptions();
@@ -454,7 +453,7 @@ TEST_F(DBSSTTest, DestroyDBWithRateLimitedDelete) {
   int bg_delete_file = 0;
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DeleteScheduler::DeleteTrashFile:DeleteFile",
-      [&](void* /*arg*/) { bg_delete_file++; });
+      [&](void* arg) { bg_delete_file++; });
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();
 
   Status s;
@@ -547,7 +546,7 @@ TEST_F(DBSSTTest, DBWithMaxSpaceAllowedRandomized) {
 
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "CompactionJob::FinishCompactionOutputFile:MaxAllowedSpaceReached",
-      [&](void* /*arg*/) {
+      [&](void* arg) {
         bg_error_set = true;
         GetAllSSTFiles(&total_sst_files_size);
         reached_max_space_on_compaction++;

db/db_tailing_iter_test.cc

@@ -157,10 +157,10 @@ TEST_F(DBTestTailingIterator, TailingIteratorTrimSeekToNext) {
       });
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "ForwardIterator::RenewIterators:Null",
-      [&](void* /*arg*/) { file_iters_renewed_null = true; });
+      [&](void* arg) { file_iters_renewed_null = true; });
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "ForwardIterator::RenewIterators:Copy",
-      [&](void* /*arg*/) { file_iters_renewed_copy = true; });
+      [&](void* arg) { file_iters_renewed_copy = true; });
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();
   const int num_records = 1000;
   for (int i = 1; i < num_records; ++i) {
@@ -415,7 +415,7 @@ TEST_F(DBTestTailingIterator, TailingIteratorUpperBound) {
   int immutable_seeks = 0;
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "ForwardIterator::SeekInternal:Immutable",
-      [&](void* /*arg*/) { ++immutable_seeks; });
+      [&](void* arg) { ++immutable_seeks; });
 
   // Seek to 13. This should not require any immutable seeks.
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();

db/db_test.cc

@@ -231,11 +231,11 @@ TEST_F(DBTest, SkipDelay) {
       std::atomic<int> sleep_count(0);
       rocksdb::SyncPoint::GetInstance()->SetCallBack(
           "DBImpl::DelayWrite:Sleep",
-          [&](void* /*arg*/) { sleep_count.fetch_add(1); });
+          [&](void* arg) { sleep_count.fetch_add(1); });
       std::atomic<int> wait_count(0);
       rocksdb::SyncPoint::GetInstance()->SetCallBack(
           "DBImpl::DelayWrite:Wait",
-          [&](void* /*arg*/) { wait_count.fetch_add(1); });
+          [&](void* arg) { wait_count.fetch_add(1); });
       rocksdb::SyncPoint::GetInstance()->EnableProcessing();
 
       WriteOptions wo;
@@ -715,9 +715,9 @@ TEST_F(DBTest, FlushSchedule) {
 namespace {
 class KeepFilter : public CompactionFilter {
  public:
-  virtual bool Filter(int /*level*/, const Slice& /*key*/,
+  virtual 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;
   }
 
@@ -747,9 +747,9 @@ class KeepFilterFactory : public CompactionFilterFactory {
 class DelayFilter : public CompactionFilter {
  public:
   explicit DelayFilter(DBTestBase* d) : db_test(d) {}
-  virtual bool Filter(int /*level*/, const Slice& /*key*/,
+  virtual 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;
   }
@@ -764,7 +764,7 @@ class DelayFilterFactory : public CompactionFilterFactory {
  public:
   explicit DelayFilterFactory(DBTestBase* d) : db_test(d) {}
   virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
-      const CompactionFilter::Context& /*context*/) override {
+      const CompactionFilter::Context& context) override {
     return std::unique_ptr<CompactionFilter>(new DelayFilter(db_test));
   }
 
@@ -2210,17 +2210,17 @@ class ModelDB : public DB {
     return Write(o, &batch);
   }
   using DB::Get;
-  virtual Status Get(const ReadOptions& /*options*/, ColumnFamilyHandle* /*cf*/,
+  virtual 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(
-      const ReadOptions& /*options*/,
+      const ReadOptions& options,
-      const std::vector<ColumnFamilyHandle*>& /*column_family*/,
+      const std::vector<ColumnFamilyHandle*>& column_family,
       const std::vector<Slice>& keys,
-      std::vector<std::string>* /*values*/) override {
+      std::vector<std::string>* values) override {
     std::vector<Status> s(keys.size(),
                           Status::NotSupported("Not implemented."));
     return s;
@@ -2229,30 +2229,30 @@ class ModelDB : public DB {
 #ifndef ROCKSDB_LITE
   using DB::IngestExternalFile;
   virtual Status IngestExternalFile(
-      ColumnFamilyHandle* /*column_family*/,
+      ColumnFamilyHandle* column_family,
-      const std::vector<std::string>& /*external_files*/,
+      const std::vector<std::string>& external_files,
-      const IngestExternalFileOptions& /*options*/) override {
+      const IngestExternalFileOptions& options) override {
     return Status::NotSupported("Not implemented.");
   }
 
   using DB::GetPropertiesOfAllTables;
   virtual Status GetPropertiesOfAllTables(
-      ColumnFamilyHandle* /*column_family*/,
+      ColumnFamilyHandle* column_family,
-      TablePropertiesCollection* /*props*/) override {
+      TablePropertiesCollection* props) override {
     return Status();
   }
 
   virtual Status GetPropertiesOfTablesInRange(
-      ColumnFamilyHandle* /*column_family*/, const Range* /*range*/,
+      ColumnFamilyHandle* column_family, const Range* range, std::size_t n,
-      std::size_t /*n*/, TablePropertiesCollection* /*props*/) override {
+      TablePropertiesCollection* props) override {
     return Status();
   }
 #endif  // ROCKSDB_LITE
 
   using DB::KeyMayExist;
-  virtual bool KeyMayExist(const ReadOptions& /*options*/,
+  virtual 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 {
     if (value_found != nullptr) {
       *value_found = false;
@@ -2260,9 +2260,8 @@ class ModelDB : public DB {
     return true;  // Not Supported directly
   }
   using DB::NewIterator;
-  virtual Iterator* NewIterator(
+  virtual 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_;
@@ -2274,9 +2273,9 @@ class ModelDB : public DB {
     }
   }
   virtual 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 {
@@ -2289,7 +2288,7 @@ class ModelDB : public DB {
     delete reinterpret_cast<const ModelSnapshot*>(snapshot);
   }
 
-  virtual Status Write(const WriteOptions& /*options*/,
+  virtual Status Write(const WriteOptions& options,
                        WriteBatch* batch) override {
     class Handler : public WriteBatch::Handler {
      public:
@@ -2297,8 +2296,7 @@ class ModelDB : public DB {
       virtual void Put(const Slice& key, const Slice& value) override {
         (*map_)[key.ToString()] = value.ToString();
       }
-      virtual void Merge(const Slice& /*key*/,
+      virtual void Merge(const Slice& key, const Slice& value) override {
-                         const Slice& /*value*/) override {
         // ignore merge for now
         // (*map_)[key.ToString()] = value.ToString();
       }
@@ -2312,65 +2310,62 @@ class ModelDB : public DB {
   }
 
   using DB::GetProperty;
-  virtual bool GetProperty(ColumnFamilyHandle* /*column_family*/,
+  virtual 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*/,
+  virtual 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(
+  virtual bool GetMapProperty(ColumnFamilyHandle* column_family,
-      ColumnFamilyHandle* /*column_family*/, const Slice& /*property*/,
+                              const Slice& property,
-      std::map<std::string, double>* /*value*/) override {
+                              std::map<std::string, double>* value) override {
     return false;
   }
   using DB::GetAggregatedIntProperty;
-  virtual bool GetAggregatedIntProperty(const Slice& /*property*/,
+  virtual bool GetAggregatedIntProperty(const Slice& property,
-                                        uint64_t* /*value*/) override {
+                                        uint64_t* value) override {
     return false;
   }
   using DB::GetApproximateSizes;
-  virtual void GetApproximateSizes(ColumnFamilyHandle* /*column_family*/,
+  virtual 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 {
     for (int i = 0; i < n; i++) {
       sizes[i] = 0;
     }
   }
   using DB::GetApproximateMemTableStats;
-  virtual void GetApproximateMemTableStats(
+  virtual 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*/,
+  virtual 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(
-      const std::unordered_map<std::string, std::string>& /*new_options*/)
+      const std::unordered_map<std::string, std::string>& new_options)
       override {
     return Status::NotSupported("Not supported operation.");
   }
 
   using DB::CompactFiles;
-  virtual Status CompactFiles(
+  virtual Status CompactFiles(const CompactionOptions& compact_options,
-      const CompactionOptions& /*compact_options*/,
+                              ColumnFamilyHandle* column_family,
-      ColumnFamilyHandle* /*column_family*/,
+                              const std::vector<std::string>& input_file_names,
-      const std::vector<std::string>& /*input_file_names*/,
+                              const int output_level,
-      const int /*output_level*/, const int /*output_path_id*/ = -1) override {
+                              const int output_path_id = -1) override {
     return Status::NotSupported("Not supported operation.");
   }
 
@@ -2383,25 +2378,24 @@ class ModelDB : public DB {
   }
 
   Status EnableAutoCompaction(
-      const std::vector<ColumnFamilyHandle*>& /*column_family_handles*/)
+      const std::vector<ColumnFamilyHandle*>& column_family_handles) override {
-      override {
     return Status::NotSupported("Not supported operation.");
   }
 
   using DB::NumberLevels;
-  virtual int NumberLevels(ColumnFamilyHandle* /*column_family*/) override {
+  virtual int NumberLevels(ColumnFamilyHandle* column_family) override {
     return 1;
   }
 
   using DB::MaxMemCompactionLevel;
   virtual int MaxMemCompactionLevel(
-      ColumnFamilyHandle* /*column_family*/) override {
+      ColumnFamilyHandle* column_family) override {
     return 1;
   }
 
   using DB::Level0StopWriteTrigger;
   virtual int Level0StopWriteTrigger(
-      ColumnFamilyHandle* /*column_family*/) override {
+      ColumnFamilyHandle* column_family) override {
     return -1;
   }
 
@@ -2410,8 +2404,7 @@ class ModelDB : public DB {
   virtual Env* GetEnv() const override { return nullptr; }
 
   using DB::GetOptions;
-  virtual Options GetOptions(
+  virtual Options GetOptions(ColumnFamilyHandle* column_family) const override {
-      ColumnFamilyHandle* /*column_family*/) const override {
     return options_;
   }
 
@@ -2419,8 +2412,8 @@ class ModelDB : public DB {
   virtual DBOptions GetDBOptions() const override { return options_; }
 
   using DB::Flush;
-  virtual Status Flush(const rocksdb::FlushOptions& /*options*/,
+  virtual Status Flush(const rocksdb::FlushOptions& options,
-                       ColumnFamilyHandle* /*column_family*/) override {
+                       ColumnFamilyHandle* column_family) override {
     Status ret;
     return ret;
   }
@@ -2430,35 +2423,33 @@ class ModelDB : public DB {
 #ifndef ROCKSDB_LITE
   virtual Status DisableFileDeletions() override { return Status::OK(); }
 
-  virtual Status EnableFileDeletions(bool /*force*/) override {
+  virtual Status EnableFileDeletions(bool force) override {
     return Status::OK();
   }
-  virtual Status GetLiveFiles(std::vector<std::string>&, uint64_t* /*size*/,
+  virtual Status GetLiveFiles(std::vector<std::string>&, uint64_t* size,
-                              bool /*flush_memtable*/ = true) override {
+                              bool flush_memtable = true) override {
     return Status::OK();
   }
 
-  virtual Status GetSortedWalFiles(VectorLogPtr& /*files*/) override {
+  virtual Status GetSortedWalFiles(VectorLogPtr& files) override {
     return Status::OK();
   }
 
-  virtual Status DeleteFile(std::string /*name*/) override {
+  virtual Status DeleteFile(std::string name) override { return Status::OK(); }
-    return Status::OK();
-  }
 
   virtual Status GetUpdatesSince(
       rocksdb::SequenceNumber, unique_ptr<rocksdb::TransactionLogIterator>*,
-      const TransactionLogIterator::ReadOptions& /*read_options*/ =
+      const TransactionLogIterator::ReadOptions& read_options =
           TransactionLogIterator::ReadOptions()) override {
     return Status::NotSupported("Not supported in Model DB");
   }
 
   virtual 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 {
+  virtual Status GetDbIdentity(std::string& identity) const override {
     return Status::OK();
   }
 
@@ -3331,7 +3322,7 @@ TEST_F(DBTest, DynamicMemtableOptions) {
 
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::DelayWrite:Wait",
-      [&](void* /*arg*/) { sleeping_task_low.WakeUp(); });
+      [&](void* arg) { sleeping_task_low.WakeUp(); });
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();
 
   while (!sleeping_task_low.WokenUp() && count < 256) {
@@ -4539,7 +4530,7 @@ class DelayedMergeOperator : public MergeOperator {
  public:
   explicit DelayedMergeOperator(DBTest* d) : db_test_(d) {}
 
-  virtual bool FullMergeV2(const MergeOperationInput& /*merge_in*/,
+  virtual bool FullMergeV2(const MergeOperationInput& merge_in,
                            MergeOperationOutput* merge_out) const override {
     db_test_->env_->addon_time_.fetch_add(1000);
     merge_out->new_value = "";
@@ -4890,7 +4881,7 @@ TEST_F(DBTest, AutomaticConflictsWithManualCompaction) {
   std::atomic<int> callback_count(0);
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction()::Conflict",
-      [&](void* /*arg*/) { callback_count.fetch_add(1); });
+      [&](void* arg) { callback_count.fetch_add(1); });
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();
   CompactRangeOptions croptions;
   croptions.exclusive_manual_compaction = false;
@@ -5089,7 +5080,7 @@ TEST_F(DBTest, HardLimit) {
 
   std::atomic<int> callback_count(0);
   rocksdb::SyncPoint::GetInstance()->SetCallBack("DBImpl::DelayWrite:Wait",
-                                                 [&](void* /*arg*/) {
+                                                 [&](void* arg) {
                                                    callback_count.fetch_add(1);
                                                    sleeping_task_low.WakeUp();
                                                  });
@@ -5182,7 +5173,7 @@ TEST_F(DBTest, SoftLimit) {
 
   // Only allow one compactin going through.
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
-      "BackgroundCallCompaction:0", [&](void* /*arg*/) {
+      "BackgroundCallCompaction:0", [&](void* arg) {
         // Schedule a sleeping task.
         sleeping_task_low.Reset();
         env_->Schedule(&test::SleepingBackgroundTask::DoSleepTask,

db/db_test2.cc

@@ -497,9 +497,9 @@ TEST_F(DBTest2, WalFilterTest) {
       apply_option_at_record_index_(apply_option_for_record_index),
       current_record_index_(0) {}
 
-    virtual WalProcessingOption LogRecord(
+    virtual 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_) {
@@ -873,10 +873,11 @@ TEST_F(DBTest2, WalFilterTestWithColumnFamilies) {
       cf_name_id_map_ = cf_name_id_map;
     }
 
-    virtual WalProcessingOption LogRecordFound(
+    virtual 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,
+      bool* batch_changed) override {
       class LogRecordBatchHandler : public WriteBatch::Handler {
       private:
         const std::map<uint32_t, uint64_t> & cf_log_number_map_;
@@ -1211,7 +1212,7 @@ class CompactionStallTestListener : public EventListener {
  public:
   CompactionStallTestListener() : compacted_files_cnt_(0) {}
 
-  void OnCompactionCompleted(DB* /*db*/, const CompactionJobInfo& ci) override {
+  void OnCompactionCompleted(DB* db, const CompactionJobInfo& ci) override {
     ASSERT_EQ(ci.cf_name, "default");
     ASSERT_EQ(ci.base_input_level, 0);
     ASSERT_EQ(ci.compaction_reason, CompactionReason::kLevelL0FilesNum);
@@ -1672,7 +1673,7 @@ TEST_F(DBTest2, SyncPointMarker) {
   std::atomic<int> sync_point_called(0);
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBTest2::MarkedPoint",
-      [&](void* /*arg*/) { sync_point_called.fetch_add(1); });
+      [&](void* arg) { sync_point_called.fetch_add(1); });
 
   // The first dependency enforces Marker can be loaded before MarkedPoint.
   // The second checks that thread 1's MarkedPoint should be disabled here.
@@ -1941,7 +1942,7 @@ TEST_F(DBTest2, AutomaticCompactionOverlapManualCompaction) {
   // can fit in L2, these 2 files will be moved to L2 and overlap with
   // the running compaction and break the LSM consistency.
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
-      "CompactionJob::Run():Start", [&](void* /*arg*/) {
+      "CompactionJob::Run():Start", [&](void* arg) {
         ASSERT_OK(
             dbfull()->SetOptions({{"level0_file_num_compaction_trigger", "2"},
                                   {"max_bytes_for_level_base", "1"}}));
@@ -2007,7 +2008,7 @@ TEST_F(DBTest2, ManualCompactionOverlapManualCompaction) {
   // the running compaction and break the LSM consistency.
   std::atomic<bool> flag(false);
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
-      "CompactionJob::Run():Start", [&](void* /*arg*/) {
+      "CompactionJob::Run():Start", [&](void* arg) {
         if (flag.exchange(true)) {
           // We want to make sure to call this callback only once
           return;

db/db_test_util.cc

@@ -1127,18 +1127,17 @@ UpdateStatus DBTestBase::updateInPlaceSmallerVarintSize(char* prevValue,
   }
 }
 
-UpdateStatus DBTestBase::updateInPlaceLargerSize(char* /*prevValue*/,
+UpdateStatus DBTestBase::updateInPlaceLargerSize(char* prevValue,
-                                                 uint32_t* /*prevSize*/,
+                                                 uint32_t* prevSize,
                                                  Slice delta,
                                                  std::string* newValue) {
   *newValue = std::string(delta.size(), 'c');
   return UpdateStatus::UPDATED;
 }
 
-UpdateStatus DBTestBase::updateInPlaceNoAction(char* /*prevValue*/,
+UpdateStatus DBTestBase::updateInPlaceNoAction(char* prevValue,
-                                               uint32_t* /*prevSize*/,
+                                               uint32_t* prevSize, Slice delta,
-                                               Slice /*delta*/,
+                                               std::string* newValue) {
-                                               std::string* /*newValue*/) {
   return UpdateStatus::UPDATE_FAILED;
 }
 

db/db_test_util.h

@@ -187,7 +187,7 @@ class SpecialSkipListFactory : public MemTableRepFactory {
   using MemTableRepFactory::CreateMemTableRep;
   virtual MemTableRep* CreateMemTableRep(
       const MemTableRep::KeyComparator& compare, Allocator* allocator,
-      const SliceTransform* transform, Logger* /*logger*/) override {
+      const SliceTransform* transform, Logger* logger) override {
     return new SpecialMemTableRep(
         allocator, factory_.CreateMemTableRep(compare, allocator, transform, 0),
         num_entries_flush_);

db/db_universal_compaction_test.cc

@@ -56,9 +56,9 @@ void VerifyCompactionResult(
 
 class KeepFilter : public CompactionFilter {
  public:
-  virtual bool Filter(int /*level*/, const Slice& /*key*/,
+  virtual 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
-                      bool* /*value_changed*/) const override {
+      override {
     return false;
   }
 
@@ -88,9 +88,9 @@ class KeepFilterFactory : public CompactionFilterFactory {
 class DelayFilter : public CompactionFilter {
  public:
   explicit DelayFilter(DBTestBase* d) : db_test(d) {}
-  virtual bool Filter(int /*level*/, const Slice& /*key*/,
+  virtual 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;
   }
@@ -105,7 +105,7 @@ class DelayFilterFactory : public CompactionFilterFactory {
  public:
   explicit DelayFilterFactory(DBTestBase* d) : db_test(d) {}
   virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter(
-      const CompactionFilter::Context& /*context*/) override {
+      const CompactionFilter::Context& context) override {
     return std::unique_ptr<CompactionFilter>(new DelayFilter(db_test));
   }
 
@@ -522,7 +522,7 @@ TEST_P(DBTestUniversalCompactionMultiLevels, UniversalCompactionTrivialMove) {
   int32_t non_trivial_move = 0;
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:TrivialMove",
-      [&](void* /*arg*/) { trivial_move++; });
+      [&](void* arg) { trivial_move++; });
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:NonTrivial", [&](void* arg) {
         non_trivial_move++;
@@ -593,23 +593,23 @@ TEST_P(DBTestUniversalCompactionParallel, UniversalCompactionParallel) {
   // Delay every compaction so multiple compactions will happen.
   std::atomic<int> num_compactions_running(0);
   std::atomic<bool> has_parallel(false);
-  rocksdb::SyncPoint::GetInstance()->SetCallBack(
+  rocksdb::SyncPoint::GetInstance()->SetCallBack("CompactionJob::Run():Start",
-      "CompactionJob::Run():Start", [&](void* /*arg*/) {
+                                                 [&](void* arg) {
-        if (num_compactions_running.fetch_add(1) > 0) {
+    if (num_compactions_running.fetch_add(1) > 0) {
-          has_parallel.store(true);
+      has_parallel.store(true);
-          return;
+      return;
-        }
+    }
-        for (int nwait = 0; nwait < 20000; nwait++) {
+    for (int nwait = 0; nwait < 20000; nwait++) {
-          if (has_parallel.load() || num_compactions_running.load() > 1) {
+      if (has_parallel.load() || num_compactions_running.load() > 1) {
-            has_parallel.store(true);
+        has_parallel.store(true);
-            break;
+        break;
-          }
+      }
-          env_->SleepForMicroseconds(1000);
+      env_->SleepForMicroseconds(1000);
-        }
+    }
-      });
+  });
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "CompactionJob::Run():End",
-      [&](void* /*arg*/) { num_compactions_running.fetch_add(-1); });
+      [&](void* arg) { num_compactions_running.fetch_add(-1); });
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();
 
   options = CurrentOptions(options);
@@ -984,7 +984,7 @@ TEST_P(DBTestUniversalCompaction, UniversalCompactionTrivialMoveTest1) {
   int32_t non_trivial_move = 0;
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:TrivialMove",
-      [&](void* /*arg*/) { trivial_move++; });
+      [&](void* arg) { trivial_move++; });
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:NonTrivial", [&](void* arg) {
         non_trivial_move++;
@@ -1030,7 +1030,7 @@ TEST_P(DBTestUniversalCompaction, UniversalCompactionTrivialMoveTest2) {
   int32_t trivial_move = 0;
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:TrivialMove",
-      [&](void* /*arg*/) { trivial_move++; });
+      [&](void* arg) { trivial_move++; });
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:NonTrivial", [&](void* arg) {
         ASSERT_TRUE(arg != nullptr);

db/deletefile_test.cc

@@ -159,7 +159,7 @@ class DeleteFileTest : public testing::Test {
   }
 
   // An empty job to guard all jobs are processed
-  static void GuardFinish(void* /*arg*/) {
+  static void GuardFinish(void* arg) {
     TEST_SYNC_POINT("DeleteFileTest::GuardFinish");
   }
 };

db/external_sst_file_test.cc

@@ -395,9 +395,8 @@ class SstFileWriterCollector : public TablePropertiesCollector {
     return Status::OK();
   }
 
-  Status AddUserKey(const Slice& /*user_key*/, const Slice& /*value*/,
+  Status AddUserKey(const Slice& user_key, const Slice& value, EntryType type,
-                    EntryType /*type*/, SequenceNumber /*seq*/,
+                    SequenceNumber seq, uint64_t file_size) override {
-                    uint64_t /*file_size*/) override {
     ++count_;
     return Status::OK();
   }
@@ -417,7 +416,7 @@ class SstFileWriterCollectorFactory : public TablePropertiesCollectorFactory {
   explicit SstFileWriterCollectorFactory(std::string prefix)
       : prefix_(prefix), num_created_(0) {}
   virtual TablePropertiesCollector* CreateTablePropertiesCollector(
-      TablePropertiesCollectorFactory::Context /*context*/) override {
+      TablePropertiesCollectorFactory::Context context) override {
     num_created_++;
     return new SstFileWriterCollector(prefix_);
   }
@@ -688,7 +687,7 @@ TEST_F(ExternalSSTFileTest, PurgeObsoleteFilesBug) {
   DestroyAndReopen(options);
 
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
-      "DBImpl::AddFile:FileCopied", [&](void* /*arg*/) {
+      "DBImpl::AddFile:FileCopied", [&](void* arg) {
         ASSERT_OK(Put("aaa", "bbb"));
         ASSERT_OK(Flush());
         ASSERT_OK(Put("aaa", "xxx"));
@@ -1127,7 +1126,7 @@ TEST_F(ExternalSSTFileTest, PickedLevelBug) {
   std::atomic<bool> bg_compact_started(false);
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BackgroundCompaction:Start",
-      [&](void* /*arg*/) { bg_compact_started.store(true); });
+      [&](void* arg) { bg_compact_started.store(true); });
 
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();
 
@@ -1408,7 +1407,7 @@ TEST_F(ExternalSSTFileTest, AddFileTrivialMoveBug) {
   ASSERT_OK(GenerateAndAddExternalFile(options, {22, 23}, 6));  // L2
 
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
-      "CompactionJob::Run():Start", [&](void* /*arg*/) {
+      "CompactionJob::Run():Start", [&](void* arg) {
         // fit in L3 but will overlap with compaction so will be added
         // to L2 but a compaction will trivially move it to L3
         // and break LSM consistency
@@ -1798,7 +1797,7 @@ TEST_F(ExternalSSTFileTest, FileWithCFInfo) {
 
 class TestIngestExternalFileListener : public EventListener {
  public:
-  void OnExternalFileIngested(DB* /*db*/,
+  void OnExternalFileIngested(DB* db,
                               const ExternalFileIngestionInfo& info) override {
     ingested_files.push_back(info);
   }

db/fault_injection_test.cc

@@ -463,10 +463,10 @@ TEST_P(FaultInjectionTest, UninstalledCompaction) {
 
   std::atomic<bool> opened(false);
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
-      "DBImpl::Open:Opened", [&](void* /*arg*/) { opened.store(true); });
+      "DBImpl::Open:Opened", [&](void* arg) { opened.store(true); });
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::BGWorkCompaction",
-      [&](void* /*arg*/) { ASSERT_TRUE(opened.load()); });
+      [&](void* arg) { ASSERT_TRUE(opened.load()); });
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();
   ASSERT_OK(OpenDB());
   ASSERT_OK(Verify(0, kNumKeys, FaultInjectionTest::kValExpectFound));

db/file_indexer_test.cc

@@ -36,10 +36,10 @@ class IntComparator : public Comparator {
 
   const char* Name() const override { return "IntComparator"; }
 
-  void FindShortestSeparator(std::string* /*start*/,
+  void FindShortestSeparator(std::string* start,
-                             const Slice& /*limit*/) const override {}
+                             const Slice& limit) const override {}
 
-  void FindShortSuccessor(std::string* /*key*/) const override {}
+  void FindShortSuccessor(std::string* key) const override {}
 };
 
 class FileIndexerTest : public testing::Test {

db/forward_iterator.cc

@@ -104,7 +104,7 @@ class LevelIterator : public InternalIterator {
     file_iter_->Seek(internal_key);
     valid_ = file_iter_->Valid();
   }
-  void SeekForPrev(const Slice& /*internal_key*/) override {
+  void SeekForPrev(const Slice& internal_key) override {
     status_ = Status::NotSupported("LevelIterator::SeekForPrev()");
     valid_ = false;
   }

db/forward_iterator.h

@@ -55,7 +55,7 @@ class ForwardIterator : public InternalIterator {
                   ColumnFamilyData* cfd, SuperVersion* current_sv = nullptr);
   virtual ~ForwardIterator();
 
-  void SeekForPrev(const Slice& /*target*/) override {
+  void SeekForPrev(const Slice& target) override {
     status_ = Status::NotSupported("ForwardIterator::SeekForPrev()");
     valid_ = false;
   }

db/internal_stats.cc

@@ -435,7 +435,7 @@ bool InternalStats::GetStringProperty(const DBPropertyInfo& property_info,
 }
 
 bool InternalStats::GetMapProperty(const DBPropertyInfo& property_info,
-                                   const Slice& /*property*/,
+                                   const Slice& property,
                                    std::map<std::string, double>* value) {
   assert(value != nullptr);
   assert(property_info.handle_map != nullptr);
@@ -487,7 +487,7 @@ bool InternalStats::HandleCompressionRatioAtLevelPrefix(std::string* value,
   return true;
 }
 
-bool InternalStats::HandleLevelStats(std::string* value, Slice /*suffix*/) {
+bool InternalStats::HandleLevelStats(std::string* value, Slice suffix) {
   char buf[1000];
   const auto* vstorage = cfd_->current()->storage_info();
   snprintf(buf, sizeof(buf),
@@ -519,36 +519,35 @@ bool InternalStats::HandleCFMapStats(std::map<std::string, double>* cf_stats) {
   return true;
 }
 
-bool InternalStats::HandleCFStats(std::string* value, Slice /*suffix*/) {
+bool InternalStats::HandleCFStats(std::string* value, Slice suffix) {
   DumpCFStats(value);
   return true;
 }
 
 bool InternalStats::HandleCFStatsNoFileHistogram(std::string* value,
-                                                 Slice /*suffix*/) {
+                                                 Slice suffix) {
   DumpCFStatsNoFileHistogram(value);
   return true;
 }
 
-bool InternalStats::HandleCFFileHistogram(std::string* value,
+bool InternalStats::HandleCFFileHistogram(std::string* value, Slice suffix) {
-                                          Slice /*suffix*/) {
   DumpCFFileHistogram(value);
   return true;
 }
 
-bool InternalStats::HandleDBStats(std::string* value, Slice /*suffix*/) {
+bool InternalStats::HandleDBStats(std::string* value, Slice suffix) {
   DumpDBStats(value);
   return true;
 }
 
-bool InternalStats::HandleSsTables(std::string* value, Slice /*suffix*/) {
+bool InternalStats::HandleSsTables(std::string* value, Slice suffix) {
   auto* current = cfd_->current();
   *value = current->DebugString(true, true);
   return true;
 }
 
 bool InternalStats::HandleAggregatedTableProperties(std::string* value,
-                                                    Slice /*suffix*/) {
+                                                    Slice suffix) {
   std::shared_ptr<const TableProperties> tp;
   auto s = cfd_->current()->GetAggregatedTableProperties(&tp);
   if (!s.ok()) {
@@ -575,34 +574,34 @@ bool InternalStats::HandleAggregatedTablePropertiesAtLevel(std::string* value,
   return true;
 }
 
-bool InternalStats::HandleNumImmutableMemTable(uint64_t* value, DBImpl* /*db*/,
+bool InternalStats::HandleNumImmutableMemTable(uint64_t* value, DBImpl* db,
-                                               Version* /*version*/) {
+                                               Version* version) {
   *value = cfd_->imm()->NumNotFlushed();
   return true;
 }
 
 bool InternalStats::HandleNumImmutableMemTableFlushed(uint64_t* value,
-                                                      DBImpl* /*db*/,
+                                                      DBImpl* db,
-                                                      Version* /*version*/) {
+                                                      Version* version) {
   *value = cfd_->imm()->NumFlushed();
   return true;
 }
 
-bool InternalStats::HandleMemTableFlushPending(uint64_t* value, DBImpl* /*db*/,
+bool InternalStats::HandleMemTableFlushPending(uint64_t* value, DBImpl* db,
-                                               Version* /*version*/) {
+                                               Version* version) {
   // Return number of mem tables that are ready to flush (made immutable)
   *value = (cfd_->imm()->IsFlushPending() ? 1 : 0);
   return true;
 }
 
 bool InternalStats::HandleNumRunningFlushes(uint64_t* value, DBImpl* db,
-                                            Version* /*version*/) {
+                                            Version* version) {
   *value = db->num_running_flushes();
   return true;
 }
 
-bool InternalStats::HandleCompactionPending(uint64_t* value, DBImpl* /*db*/,
+bool InternalStats::HandleCompactionPending(uint64_t* value, DBImpl* db,
-                                            Version* /*version*/) {
+                                            Version* version) {
   // 1 if the system already determines at least one compaction is needed.
   // 0 otherwise,
   const auto* vstorage = cfd_->current()->storage_info();
@@ -611,74 +610,70 @@ bool InternalStats::HandleCompactionPending(uint64_t* value, DBImpl* /*db*/,
 }
 
 bool InternalStats::HandleNumRunningCompactions(uint64_t* value, DBImpl* db,
-                                                Version* /*version*/) {
+                                                Version* version) {
   *value = db->num_running_compactions_;
   return true;
 }
 
-bool InternalStats::HandleBackgroundErrors(uint64_t* value, DBImpl* /*db*/,
+bool InternalStats::HandleBackgroundErrors(uint64_t* value, DBImpl* db,
-                                           Version* /*version*/) {
+                                           Version* version) {
   // Accumulated number of  errors in background flushes or compactions.
   *value = GetBackgroundErrorCount();
   return true;
 }
 
-bool InternalStats::HandleCurSizeActiveMemTable(uint64_t* value, DBImpl* /*db*/,
+bool InternalStats::HandleCurSizeActiveMemTable(uint64_t* value, DBImpl* db,
-                                                Version* /*version*/) {
+                                                Version* version) {
   // Current size of the active memtable
   *value = cfd_->mem()->ApproximateMemoryUsage();
   return true;
 }
 
-bool InternalStats::HandleCurSizeAllMemTables(uint64_t* value, DBImpl* /*db*/,
+bool InternalStats::HandleCurSizeAllMemTables(uint64_t* value, DBImpl* db,
-                                              Version* /*version*/) {
+                                              Version* version) {
   // Current size of the active memtable + immutable memtables
   *value = cfd_->mem()->ApproximateMemoryUsage() +
            cfd_->imm()->ApproximateUnflushedMemTablesMemoryUsage();
   return true;
 }
 
-bool InternalStats::HandleSizeAllMemTables(uint64_t* value, DBImpl* /*db*/,
+bool InternalStats::HandleSizeAllMemTables(uint64_t* value, DBImpl* db,
-                                           Version* /*version*/) {
+                                           Version* version) {
   *value = cfd_->mem()->ApproximateMemoryUsage() +
            cfd_->imm()->ApproximateMemoryUsage();
   return true;
 }
 
-bool InternalStats::HandleNumEntriesActiveMemTable(uint64_t* value,
+bool InternalStats::HandleNumEntriesActiveMemTable(uint64_t* value, DBImpl* db,
-                                                   DBImpl* /*db*/,
+                                                   Version* version) {
-                                                   Version* /*version*/) {
   // Current number of entires in the active memtable
   *value = cfd_->mem()->num_entries();
   return true;
 }
 
-bool InternalStats::HandleNumEntriesImmMemTables(uint64_t* value,
+bool InternalStats::HandleNumEntriesImmMemTables(uint64_t* value, DBImpl* db,
-                                                 DBImpl* /*db*/,
+                                                 Version* version) {
-                                                 Version* /*version*/) {
   // Current number of entries in the immutable memtables
   *value = cfd_->imm()->current()->GetTotalNumEntries();
   return true;
 }
 
-bool InternalStats::HandleNumDeletesActiveMemTable(uint64_t* value,
+bool InternalStats::HandleNumDeletesActiveMemTable(uint64_t* value, DBImpl* db,
-                                                   DBImpl* /*db*/,
+                                                   Version* version) {
-                                                   Version* /*version*/) {
   // Current number of entires in the active memtable
   *value = cfd_->mem()->num_deletes();
   return true;
 }
 
-bool InternalStats::HandleNumDeletesImmMemTables(uint64_t* value,
+bool InternalStats::HandleNumDeletesImmMemTables(uint64_t* value, DBImpl* db,
-                                                 DBImpl* /*db*/,
+                                                 Version* version) {
-                                                 Version* /*version*/) {
   // Current number of entries in the immutable memtables
   *value = cfd_->imm()->current()->GetTotalNumDeletes();
   return true;
 }
 
-bool InternalStats::HandleEstimateNumKeys(uint64_t* value, DBImpl* /*db*/,
+bool InternalStats::HandleEstimateNumKeys(uint64_t* value, DBImpl* db,
-                                          Version* /*version*/) {
+                                          Version* version) {
   // Estimate number of entries in the column family:
   // Use estimated entries in tables + total entries in memtables.
   const auto* vstorage = cfd_->current()->storage_info();
@@ -694,79 +689,77 @@ bool InternalStats::HandleEstimateNumKeys(uint64_t* value, DBImpl* /*db*/,
 }
 
 bool InternalStats::HandleNumSnapshots(uint64_t* value, DBImpl* db,
-                                       Version* /*version*/) {
+                                       Version* version) {
   *value = db->snapshots().count();
   return true;
 }
 
 bool InternalStats::HandleOldestSnapshotTime(uint64_t* value, DBImpl* db,
-                                             Version* /*version*/) {
+                                             Version* version) {
   *value = static_cast<uint64_t>(db->snapshots().GetOldestSnapshotTime());
   return true;
 }
 
-bool InternalStats::HandleNumLiveVersions(uint64_t* value, DBImpl* /*db*/,
+bool InternalStats::HandleNumLiveVersions(uint64_t* value, DBImpl* db,
-                                          Version* /*version*/) {
+                                          Version* version) {
   *value = cfd_->GetNumLiveVersions();
   return true;
 }
 
-bool InternalStats::HandleCurrentSuperVersionNumber(uint64_t* value,
+bool InternalStats::HandleCurrentSuperVersionNumber(uint64_t* value, DBImpl* db,
-                                                    DBImpl* /*db*/,
+                                                    Version* version) {
-                                                    Version* /*version*/) {
   *value = cfd_->GetSuperVersionNumber();
   return true;
 }
 
 bool InternalStats::HandleIsFileDeletionsEnabled(uint64_t* value, DBImpl* db,
-                                                 Version* /*version*/) {
+                                                 Version* version) {
   *value = db->IsFileDeletionsEnabled();
   return true;
 }
 
-bool InternalStats::HandleBaseLevel(uint64_t* value, DBImpl* /*db*/,
+bool InternalStats::HandleBaseLevel(uint64_t* value, DBImpl* db,
-                                    Version* /*version*/) {
+                                    Version* version) {
   const auto* vstorage = cfd_->current()->storage_info();
   *value = vstorage->base_level();
   return true;
 }
 
-bool InternalStats::HandleTotalSstFilesSize(uint64_t* value, DBImpl* /*db*/,
+bool InternalStats::HandleTotalSstFilesSize(uint64_t* value, DBImpl* db,
-                                            Version* /*version*/) {
+                                            Version* version) {
   *value = cfd_->GetTotalSstFilesSize();
   return true;
 }
 
 bool InternalStats::HandleEstimatePendingCompactionBytes(uint64_t* value,
-                                                         DBImpl* /*db*/,
+                                                         DBImpl* db,
-                                                         Version* /*version*/) {
+                                                         Version* version) {
   const auto* vstorage = cfd_->current()->storage_info();
   *value = vstorage->estimated_compaction_needed_bytes();
   return true;
 }
 
-bool InternalStats::HandleEstimateTableReadersMem(uint64_t* value,
+bool InternalStats::HandleEstimateTableReadersMem(uint64_t* value, DBImpl* db,
-                                                  DBImpl* /*db*/,
                                                   Version* version) {
   *value = (version == nullptr) ? 0 : version->GetMemoryUsageByTableReaders();
   return true;
 }
 
-bool InternalStats::HandleEstimateLiveDataSize(uint64_t* value, DBImpl* /*db*/,
+bool InternalStats::HandleEstimateLiveDataSize(uint64_t* value, DBImpl* db,
-                                               Version* /*version*/) {
+                                               Version* version) {
   const auto* vstorage = cfd_->current()->storage_info();
   *value = vstorage->EstimateLiveDataSize();
   return true;
 }
 
 bool InternalStats::HandleMinLogNumberToKeep(uint64_t* value, DBImpl* db,
-                                             Version* /*version*/) {
+                                             Version* version) {
   *value = db->MinLogNumberToKeep();
   return true;
 }
 
 bool InternalStats::HandleActualDelayedWriteRate(uint64_t* value, DBImpl* db,
-                                                 Version* /*version*/) {
+                                                 Version* version) {
   const WriteController& wc = db->write_controller();
   if (!wc.NeedsDelay()) {
     *value = 0;
@@ -777,7 +770,7 @@ bool InternalStats::HandleActualDelayedWriteRate(uint64_t* value, DBImpl* db,
 }
 
 bool InternalStats::HandleIsWriteStopped(uint64_t* value, DBImpl* db,
-                                         Version* /*version*/) {
+                                         Version* version) {
   *value = db->write_controller().IsStopped() ? 1 : 0;
   return true;
 }

db/listener_test.cc

@@ -46,11 +46,11 @@ class EventListenerTest : public DBTestBase {
 };
 
 struct TestPropertiesCollector : public rocksdb::TablePropertiesCollector {
-  virtual rocksdb::Status AddUserKey(const rocksdb::Slice& /*key*/,
+  virtual 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(
@@ -73,7 +73,7 @@ struct TestPropertiesCollector : public rocksdb::TablePropertiesCollector {
 class TestPropertiesCollectorFactory : public TablePropertiesCollectorFactory {
  public:
   virtual TablePropertiesCollector* CreateTablePropertiesCollector(
-      TablePropertiesCollectorFactory::Context /*context*/) override {
+      TablePropertiesCollectorFactory::Context context) override {
     return new TestPropertiesCollector;
   }
   const char* Name() const override { return "TestTablePropertiesCollector"; }
@@ -425,7 +425,7 @@ TEST_F(EventListenerTest, DisableBGCompaction) {
 
 class TestCompactionReasonListener : public EventListener {
  public:
-  void OnCompactionCompleted(DB* /*db*/, const CompactionJobInfo& ci) override {
+  void OnCompactionCompleted(DB* db, const CompactionJobInfo& ci) override {
     std::lock_guard<std::mutex> lock(mutex_);
     compaction_reasons_.push_back(ci.compaction_reason);
   }
@@ -807,8 +807,7 @@ class BackgroundErrorListener : public EventListener {
  public:
   BackgroundErrorListener(SpecialEnv* env) : env_(env), counter_(0) {}
 
-  void OnBackgroundError(BackgroundErrorReason /*reason*/,
+  void OnBackgroundError(BackgroundErrorReason reason, Status* bg_error) override {
-                         Status* bg_error) override {
     if (counter_ == 0) {
       // suppress the first error and disable write-dropping such that a retry
       // can succeed.

db/malloc_stats.cc

@@ -36,7 +36,7 @@ static void GetJemallocStatus(void* mstat_arg, const char* status) {
 }
 #endif  // ROCKSDB_JEMALLOC
 
-void DumpMallocStats(std::string* /*stats*/) {
+void DumpMallocStats(std::string* stats) {
 #ifdef ROCKSDB_JEMALLOC
   MallocStatus mstat;
   const unsigned int kMallocStatusLen = 1000000;

db/manual_compaction_test.cc

@@ -46,9 +46,9 @@ class DestroyAllCompactionFilter : public CompactionFilter {
  public:
   DestroyAllCompactionFilter() {}
 
-  virtual bool Filter(int /*level*/, const Slice& /*key*/,
+  virtual 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";
   }
 

db/memtable_list.cc

@@ -152,7 +152,7 @@ bool MemTableListVersion::GetFromList(std::list<MemTable*>* list,
 }
 
 Status MemTableListVersion::AddRangeTombstoneIterators(
-    const ReadOptions& read_opts, Arena* /*arena*/,
+    const ReadOptions& read_opts, Arena* arena,
     RangeDelAggregator* range_del_agg) {
   assert(range_del_agg != nullptr);
   for (auto& m : memlist_) {
@@ -298,7 +298,7 @@ void MemTableList::PickMemtablesToFlush(autovector<MemTable*>* ret) {
 }
 
 void MemTableList::RollbackMemtableFlush(const autovector<MemTable*>& mems,
-                                         uint64_t /*file_number*/) {
+                                         uint64_t file_number) {
   AutoThreadOperationStageUpdater stage_updater(
       ThreadStatus::STAGE_MEMTABLE_ROLLBACK);
   assert(!mems.empty());

db/merge_test.cc

@@ -504,7 +504,7 @@ void runTest(int argc, const std::string& dbname, const bool use_ttl = false) {
 }
 }  // namespace
 
-int main(int argc, char* /*argv*/ []) {
+int main(int argc, char *argv[]) {
   //TODO: Make this test like a general rocksdb unit-test
   rocksdb::port::InstallStackTraceHandler();
   runTest(argc, test::TmpDir() + "/merge_testdb");

db/plain_table_db_test.cc

@@ -327,7 +327,7 @@ class TestPlainTableFactory : public PlainTableFactory {
       const TableReaderOptions& table_reader_options,
       unique_ptr<RandomAccessFileReader>&& file, uint64_t file_size,
       unique_ptr<TableReader>* table,
-      bool /*prefetch_index_and_filter_in_cache*/) const override {
+      bool prefetch_index_and_filter_in_cache) const override {
     TableProperties* props = nullptr;
     auto s =
         ReadTableProperties(file.get(), file_size, kPlainTableMagicNumber,

db/prefix_test.cc

@@ -126,10 +126,10 @@ class TestKeyComparator : public Comparator {
     return "TestKeyComparator";
   }
 
-  virtual void FindShortestSeparator(std::string* /*start*/,
+  virtual void FindShortestSeparator(std::string* start,
-                                     const Slice& /*limit*/) const override {}
+                                     const Slice& limit) const override {}
 
-  virtual void FindShortSuccessor(std::string* /*key*/) const override {}
+  virtual void FindShortSuccessor(std::string* key) const override {}
 };
 
 namespace {

db/table_cache.cc

@@ -30,7 +30,7 @@ namespace rocksdb {
 namespace {
 
 template <class T>
-static void DeleteEntry(const Slice& /*key*/, void* value) {
+static void DeleteEntry(const Slice& key, void* value) {
   T* typed_value = reinterpret_cast<T*>(value);
   delete typed_value;
 }
@@ -41,7 +41,7 @@ static void UnrefEntry(void* arg1, void* arg2) {
   cache->Release(h);
 }
 
-static void DeleteTableReader(void* arg1, void* /*arg2*/) {
+static void DeleteTableReader(void* arg1, void* arg2) {
   TableReader* table_reader = reinterpret_cast<TableReader*>(arg1);
   delete table_reader;
 }

db/table_properties_collector.cc

@@ -12,8 +12,8 @@
 namespace rocksdb {
 
 Status InternalKeyPropertiesCollector::InternalAdd(const Slice& key,
-                                                   const Slice& /*value*/,
+                                                   const Slice& value,
-                                                   uint64_t /*file_size*/) {
+                                                   uint64_t file_size) {
   ParsedInternalKey ikey;
   if (!ParseInternalKey(key, &ikey)) {
     return Status::InvalidArgument("Invalid internal key");

db/table_properties_collector.h

@@ -73,7 +73,7 @@ class InternalKeyPropertiesCollectorFactory
     : public IntTblPropCollectorFactory {
  public:
   virtual IntTblPropCollector* CreateIntTblPropCollector(
-      uint32_t /*column_family_id*/) override {
+      uint32_t column_family_id) override {
     return new InternalKeyPropertiesCollector();
   }
 

db/table_properties_collector_test.cc

@@ -82,9 +82,8 @@ class RegularKeysStartWithA: public TablePropertiesCollector {
      return Status::OK();
   }
 
-  Status AddUserKey(const Slice& user_key, const Slice& /*value*/,
+  Status AddUserKey(const Slice& user_key, const Slice& value, EntryType type,
-                    EntryType type, SequenceNumber /*seq*/,
+                    SequenceNumber seq, uint64_t file_size) override {
-                    uint64_t file_size) override {
     // simply asssume all user keys are not empty.
     if (user_key.data()[0] == 'A') {
       ++count_;
@@ -134,7 +133,7 @@ class RegularKeysStartWithABackwardCompatible
     return Status::OK();
   }
 
-  Status Add(const Slice& user_key, const Slice& /*value*/) override {
+  Status Add(const Slice& user_key, const Slice& value) override {
     // simply asssume all user keys are not empty.
     if (user_key.data()[0] == 'A') {
       ++count_;
@@ -162,8 +161,8 @@ class RegularKeysStartWithAInternal : public IntTblPropCollector {
     return Status::OK();
   }
 
-  Status InternalAdd(const Slice& user_key, const Slice& /*value*/,
+  Status InternalAdd(const Slice& user_key, const Slice& value,
-                     uint64_t /*file_size*/) override {
+                     uint64_t file_size) override {
     // simply asssume all user keys are not empty.
     if (user_key.data()[0] == 'A') {
       ++count_;
@@ -194,7 +193,7 @@ class RegularKeysStartWithAFactory : public IntTblPropCollectorFactory,
     }
   }
   virtual IntTblPropCollector* CreateIntTblPropCollector(
-      uint32_t /*column_family_id*/) override {
+      uint32_t column_family_id) override {
     return new RegularKeysStartWithAInternal();
   }
   const char* Name() const override { return "RegularKeysStartWithA"; }
@@ -204,7 +203,7 @@ class RegularKeysStartWithAFactory : public IntTblPropCollectorFactory,
 
 class FlushBlockEveryThreePolicy : public FlushBlockPolicy {
  public:
-  virtual bool Update(const Slice& /*key*/, const Slice& /*value*/) override {
+  virtual bool Update(const Slice& key, const Slice& value) override {
     return (++count_ % 3U == 0);
   }
 
@@ -221,8 +220,8 @@ class FlushBlockEveryThreePolicyFactory : public FlushBlockPolicyFactory {
   }
 
   FlushBlockPolicy* NewFlushBlockPolicy(
-      const BlockBasedTableOptions& /*table_options*/,
+      const BlockBasedTableOptions& table_options,
-      const BlockBuilder& /*data_block_builder*/) const override {
+      const BlockBuilder& data_block_builder) const override {
     return new FlushBlockEveryThreePolicy;
   }
 };

db/version_builder.cc

@@ -185,7 +185,7 @@ class VersionBuilder::Rep {
     }
   }
 
-  void CheckConsistencyForDeletes(VersionEdit* /*edit*/, uint64_t number,
+  void CheckConsistencyForDeletes(VersionEdit* edit, uint64_t number,
                                   int level) {
 #ifdef NDEBUG
     if (!base_vstorage_->force_consistency_checks()) {

db/version_edit.cc

@@ -198,7 +198,7 @@ static bool GetInternalKey(Slice* input, InternalKey* dst) {
   }
 }
 
-bool VersionEdit::GetLevel(Slice* input, int* level, const char** /*msg*/) {
+bool VersionEdit::GetLevel(Slice* input, int* level, const char** msg) {
   uint32_t v;
   if (GetVarint32(input, &v)) {
     *level = v;

db/version_set.cc

@@ -528,7 +528,9 @@ class LevelFileIteratorState : public TwoLevelIteratorState {
         for_compaction_, nullptr /* arena */, skip_filters_, level_);
   }
 
-  bool PrefixMayMatch(const Slice& /*internal_key*/) override { return true; }
+  bool PrefixMayMatch(const Slice& internal_key) override {
+    return true;
+  }
 
   bool KeyReachedUpperBound(const Slice& internal_key) override {
     return read_options_.iterate_upper_bound != nullptr &&
@@ -2654,7 +2656,7 @@ void VersionSet::LogAndApplyCFHelper(VersionEdit* edit) {
 }
 
 void VersionSet::LogAndApplyHelper(ColumnFamilyData* cfd,
-                                   VersionBuilder* builder, Version* /*v*/,
+                                   VersionBuilder* builder, Version* v,
                                    VersionEdit* edit, InstrumentedMutex* mu) {
   mu->AssertHeld();
   assert(!edit->IsColumnFamilyManipulation());

db/version_set.h

@@ -792,7 +792,7 @@ class VersionSet {
 
   struct LogReporter : public log::Reader::Reporter {
     Status* status;
-    virtual void Corruption(size_t /*bytes*/, const Status& s) override {
+    virtual void Corruption(size_t bytes, const Status& s) override {
       if (this->status->ok()) *this->status = s;
     }
   };

db/version_set_test.cc

@@ -76,9 +76,7 @@ class CountingLogger : public Logger {
  public:
   CountingLogger() : log_count(0) {}
   using Logger::Logv;
-  virtual void Logv(const char* /*format*/, va_list /*ap*/) override {
+  virtual void Logv(const char* format, va_list ap) override { log_count++; }
-    log_count++;
-  }
   int log_count;
 };
 

db/wal_manager_test.cc

@@ -72,7 +72,7 @@ class WalManagerTest : public testing::Test {
   }
 
   // NOT thread safe
-  void RollTheLog(bool /*archived*/) {
+  void RollTheLog(bool archived) {
     current_log_number_++;
     std::string fname = ArchivedLogFileName(dbname_, current_log_number_);
     unique_ptr<WritableFile> file;

db/write_batch.cc

@@ -171,7 +171,7 @@ WriteBatch::~WriteBatch() { delete save_points_; }
 
 WriteBatch::Handler::~Handler() { }
 
-void WriteBatch::Handler::LogData(const Slice& /*blob*/) {
+void WriteBatch::Handler::LogData(const Slice& blob) {
   // If the user has not specified something to do with blobs, then we ignore
   // them.
 }
@@ -469,7 +469,7 @@ void WriteBatchInternal::SetSequence(WriteBatch* b, SequenceNumber seq) {
   EncodeFixed64(&b->rep_[0], seq);
 }
 
-size_t WriteBatchInternal::GetFirstOffset(WriteBatch* /*b*/) {
+size_t WriteBatchInternal::GetFirstOffset(WriteBatch* b) {
   return WriteBatchInternal::kHeader;
 }
 
@@ -1003,7 +1003,7 @@ public:
     return Status::OK();
   }
 
-  Status DeleteImpl(uint32_t /*column_family_id*/, const Slice& key,
+  Status DeleteImpl(uint32_t column_family_id, const Slice& key,
                     const Slice& value, ValueType delete_type) {
     MemTable* mem = cf_mems_->GetMemTable();
     mem->Add(sequence_, delete_type, key, value, concurrent_memtable_writes_,

db/write_batch_test.cc

@@ -434,7 +434,7 @@ TEST_F(WriteBatchTest, DISABLED_ManyUpdates) {
   struct NoopHandler : public WriteBatch::Handler {
     uint32_t num_seen = 0;
     char expected_char = 'A';
-    virtual Status PutCF(uint32_t /*column_family_id*/, const Slice& key,
+    virtual Status PutCF(uint32_t column_family_id, const Slice& key,
                          const Slice& value) override {
       EXPECT_EQ(kKeyValueSize, key.size());
       EXPECT_EQ(kKeyValueSize, value.size());
@@ -449,22 +449,22 @@ TEST_F(WriteBatchTest, DISABLED_ManyUpdates) {
       ++num_seen;
       return Status::OK();
     }
-    virtual Status DeleteCF(uint32_t /*column_family_id*/,
+    virtual Status DeleteCF(uint32_t column_family_id,
-                            const Slice& /*key*/) override {
+                            const Slice& key) override {
       ADD_FAILURE();
       return Status::OK();
     }
-    virtual Status SingleDeleteCF(uint32_t /*column_family_id*/,
+    virtual Status SingleDeleteCF(uint32_t column_family_id,
-                                  const Slice& /*key*/) override {
+                                  const Slice& key) override {
       ADD_FAILURE();
       return Status::OK();
     }
-    virtual Status MergeCF(uint32_t /*column_family_id*/, const Slice& /*key*/,
+    virtual Status MergeCF(uint32_t column_family_id, const Slice& key,
-                           const Slice& /*value*/) override {
+                           const Slice& value) override {
       ADD_FAILURE();
       return Status::OK();
     }
-    virtual void LogData(const Slice& /*blob*/) override { ADD_FAILURE(); }
+    virtual void LogData(const Slice& blob) override { ADD_FAILURE(); }
     virtual bool Continue() override { return num_seen < kNumUpdates; }
   } handler;
 
@@ -489,7 +489,7 @@ TEST_F(WriteBatchTest, DISABLED_LargeKeyValue) {
 
   struct NoopHandler : public WriteBatch::Handler {
     int num_seen = 0;
-    virtual Status PutCF(uint32_t /*column_family_id*/, const Slice& key,
+    virtual Status PutCF(uint32_t column_family_id, const Slice& key,
                          const Slice& value) override {
       EXPECT_EQ(kKeyValueSize, key.size());
       EXPECT_EQ(kKeyValueSize, value.size());
@@ -500,22 +500,22 @@ TEST_F(WriteBatchTest, DISABLED_LargeKeyValue) {
       ++num_seen;
       return Status::OK();
     }
-    virtual Status DeleteCF(uint32_t /*column_family_id*/,
+    virtual Status DeleteCF(uint32_t column_family_id,
-                            const Slice& /*key*/) override {
+                            const Slice& key) override {
       ADD_FAILURE();
       return Status::OK();
     }
-    virtual Status SingleDeleteCF(uint32_t /*column_family_id*/,
+    virtual Status SingleDeleteCF(uint32_t column_family_id,
-                                  const Slice& /*key*/) override {
+                                  const Slice& key) override {
       ADD_FAILURE();
       return Status::OK();
     }
-    virtual Status MergeCF(uint32_t /*column_family_id*/, const Slice& /*key*/,
+    virtual Status MergeCF(uint32_t column_family_id, const Slice& key,
-                           const Slice& /*value*/) override {
+                           const Slice& value) override {
       ADD_FAILURE();
       return Status::OK();
     }
-    virtual void LogData(const Slice& /*blob*/) override { ADD_FAILURE(); }
+    virtual void LogData(const Slice& blob) override { ADD_FAILURE(); }
     virtual bool Continue() override { return num_seen < 2; }
   } handler;
 

db/write_callback_test.cc

@@ -55,7 +55,9 @@ class WriteCallbackTestWriteCallback1 : public WriteCallback {
 
 class WriteCallbackTestWriteCallback2 : public WriteCallback {
  public:
-  Status Callback(DB* /*db*/) override { return Status::Busy(); }
+  Status Callback(DB *db) override {
+    return Status::Busy();
+  }
   bool AllowWriteBatching() override { return true; }
 };
 
@@ -73,7 +75,7 @@ class MockWriteCallback : public WriteCallback {
     was_called_.store(other.was_called_.load());
   }
 
-  Status Callback(DB* /*db*/) override {
+  Status Callback(DB* db) override {
     was_called_.store(true);
     if (should_fail_) {
       return Status::Busy();

db/write_thread.cc

@@ -434,8 +434,7 @@ void WriteThread::EnterAsMemTableWriter(Writer* leader,
       last_writer->sequence + WriteBatchInternal::Count(last_writer->batch) - 1;
 }
 
-void WriteThread::ExitAsMemTableWriter(Writer* /*self*/,
+void WriteThread::ExitAsMemTableWriter(Writer* self, WriteGroup& write_group) {
-                                       WriteGroup& write_group) {
   Writer* leader = write_group.leader;
   Writer* last_writer = write_group.last_writer;
 

env/env_encryption.cc

@@ -844,9 +844,7 @@ static void decodeCTRParameters(const char *prefix, size_t blockSize, uint64_t &
 
 // CreateNewPrefix initialized an allocated block of prefix memory 
 // for a new file.
-Status CTREncryptionProvider::CreateNewPrefix(const std::string& /*fname*/,
+Status CTREncryptionProvider::CreateNewPrefix(const std::string& fname, char *prefix, size_t prefixLength) {
-                                              char* prefix,
-                                              size_t prefixLength) {
   // Create & seed rnd.
   Random rnd((uint32_t)Env::Default()->NowMicros());
   // Fill entire prefix block with random values.
@@ -875,9 +873,7 @@ Status CTREncryptionProvider::CreateNewPrefix(const std::string& /*fname*/,
 // in plain text.
 // Returns the amount of space (starting from the start of the prefix)
 // that has been initialized.
-size_t CTREncryptionProvider::PopulateSecretPrefixPart(char* /*prefix*/,
+size_t CTREncryptionProvider::PopulateSecretPrefixPart(char *prefix, size_t prefixLength, size_t blockSize) {
-                                                       size_t /*prefixLength*/,
-                                                       size_t /*blockSize*/) {
   // Nothing to do here, put in custom data in override when needed.
   return 0;
 }
@@ -902,10 +898,8 @@ Status CTREncryptionProvider::CreateCipherStream(const std::string& fname, const
 
 // CreateCipherStreamFromPrefix creates a block access cipher stream for a file given
 // given name and options. The given prefix is already decrypted.
-Status CTREncryptionProvider::CreateCipherStreamFromPrefix(
+Status CTREncryptionProvider::CreateCipherStreamFromPrefix(const std::string& fname, const EnvOptions& options,
-    const std::string& /*fname*/, const EnvOptions& /*options*/,
+    uint64_t initialCounter, const Slice& iv, const Slice& prefix, unique_ptr<BlockAccessCipherStream>* result) {
-    uint64_t initialCounter, const Slice& iv, const Slice& /*prefix*/,
-    unique_ptr<BlockAccessCipherStream>* result) {
   (*result) = unique_ptr<BlockAccessCipherStream>(new CTRCipherStream(cipher_, iv.data(), initialCounter));
   return Status::OK();
 }

env/env_hdfs.cc

@@ -598,13 +598,13 @@ Status NewHdfsEnv(Env** hdfs_env, const std::string& fsname) {
 
 // dummy placeholders used when HDFS is not available
 namespace rocksdb {
-Status HdfsEnv::NewSequentialFile(const std::string& /*fname*/,
+ Status HdfsEnv::NewSequentialFile(const std::string& fname,
-                                  unique_ptr<SequentialFile>* /*result*/,
+                                   unique_ptr<SequentialFile>* result,
-                                  const EnvOptions& /*options*/) {
+                                   const EnvOptions& options) {
-  return Status::NotSupported("Not compiled with hdfs support");
+   return Status::NotSupported("Not compiled with hdfs support");
  }
 
- Status NewHdfsEnv(Env** /*hdfs_env*/, const std::string& /*fsname*/) {
+ Status NewHdfsEnv(Env** hdfs_env, const std::string& fsname) {
    return Status::NotSupported("Not compiled with hdfs support");
  }
 }

env/env_test.cc

@@ -1248,36 +1248,33 @@ TEST_P(EnvPosixTestWithParam, WritableFileWrapper) {
       inc(0);
     }
 
-    Status Append(const Slice& /*data*/) override {
+    Status Append(const Slice& data) override { inc(1); return Status::OK(); }
-      inc(1);
+    Status Truncate(uint64_t size) override { return Status::OK(); }
-      return Status::OK();
-    }
-    Status Truncate(uint64_t /*size*/) override { return Status::OK(); }
     Status Close() override { inc(2); return Status::OK(); }
     Status Flush() override { inc(3); return Status::OK(); }
     Status Sync() override { inc(4); return Status::OK(); }
     Status Fsync() override { inc(5); return Status::OK(); }
-    void SetIOPriority(Env::IOPriority /*pri*/) override { inc(6); }
+    void SetIOPriority(Env::IOPriority pri) override { inc(6); }
     uint64_t GetFileSize() override { inc(7); return 0; }
-    void GetPreallocationStatus(size_t* /*block_size*/,
+    void GetPreallocationStatus(size_t* block_size,
-                                size_t* /*last_allocated_block*/) override {
+                                size_t* last_allocated_block) override {
       inc(8);
     }
-    size_t GetUniqueId(char* /*id*/, size_t /*max_size*/) const override {
+    size_t GetUniqueId(char* id, size_t max_size) const override {
       inc(9);
       return 0;
     }
-    Status InvalidateCache(size_t /*offset*/, size_t /*length*/) override {
+    Status InvalidateCache(size_t offset, size_t length) override {
       inc(10);
       return Status::OK();
     }
 
    protected:
-    Status Allocate(uint64_t /*offset*/, uint64_t /*len*/) override {
+    Status Allocate(uint64_t offset, uint64_t len) override {
       inc(11);
       return Status::OK();
     }
-    Status RangeSync(uint64_t /*offset*/, uint64_t /*nbytes*/) override {
+    Status RangeSync(uint64_t offset, uint64_t nbytes) override {
       inc(12);
       return Status::OK();
     }

env/io_posix.cc

@@ -443,7 +443,7 @@ PosixMmapReadableFile::~PosixMmapReadableFile() {
 }
 
 Status PosixMmapReadableFile::Read(uint64_t offset, size_t n, Slice* result,
-                                   char* /*scratch*/) const {
+                                   char* scratch) const {
   Status s;
   if (offset > length_) {
     *result = Slice();
@@ -922,7 +922,7 @@ size_t PosixWritableFile::GetUniqueId(char* id, size_t max_size) const {
  */
 
 PosixRandomRWFile::PosixRandomRWFile(const std::string& fname, int fd,
-                                     const EnvOptions& /*options*/)
+                                     const EnvOptions& options)
     : filename_(fname), fd_(fd) {}
 
 PosixRandomRWFile::~PosixRandomRWFile() {

env/io_posix.h

@@ -201,7 +201,7 @@ class PosixMmapFile : public WritableFile {
 
   // Means Close() will properly take care of truncate
   // and it does not need any additional information
-  virtual Status Truncate(uint64_t /*size*/) override { return Status::OK(); }
+  virtual Status Truncate(uint64_t size) override { return Status::OK(); }
   virtual Status Close() override;
   virtual Status Append(const Slice& data) override;
   virtual Status Flush() override;

env/mock_env.cc

@@ -445,8 +445,8 @@ MockEnv::~MockEnv() {
 
   // Partial implementation of the Env interface.
 Status MockEnv::NewSequentialFile(const std::string& fname,
-                                  unique_ptr<SequentialFile>* result,
+                                     unique_ptr<SequentialFile>* result,
-                                  const EnvOptions& /*soptions*/) {
+                                     const EnvOptions& soptions) {
   auto fn = NormalizePath(fname);
   MutexLock lock(&mutex_);
   if (file_map_.find(fn) == file_map_.end()) {
@@ -462,8 +462,8 @@ Status MockEnv::NewSequentialFile(const std::string& fname,
 }
 
 Status MockEnv::NewRandomAccessFile(const std::string& fname,
-                                    unique_ptr<RandomAccessFile>* result,
+                                       unique_ptr<RandomAccessFile>* result,
-                                    const EnvOptions& /*soptions*/) {
+                                       const EnvOptions& soptions) {
   auto fn = NormalizePath(fname);
   MutexLock lock(&mutex_);
   if (file_map_.find(fn) == file_map_.end()) {
@@ -480,7 +480,7 @@ Status MockEnv::NewRandomAccessFile(const std::string& fname,
 
 Status MockEnv::NewRandomRWFile(const std::string& fname,
                                 unique_ptr<RandomRWFile>* result,
-                                const EnvOptions& /*soptions*/) {
+                                const EnvOptions& soptions) {
   auto fn = NormalizePath(fname);
   MutexLock lock(&mutex_);
   if (file_map_.find(fn) == file_map_.end()) {
@@ -523,8 +523,8 @@ Status MockEnv::NewWritableFile(const std::string& fname,
   return Status::OK();
 }
 
-Status MockEnv::NewDirectory(const std::string& /*name*/,
+Status MockEnv::NewDirectory(const std::string& name,
-                             unique_ptr<Directory>* result) {
+                                unique_ptr<Directory>* result) {
   result->reset(new MockEnvDirectory());
   return Status::OK();
 }

hdfs/env_hdfs.h

@@ -245,7 +245,7 @@ static const Status notsup;
 class HdfsEnv : public Env {
 
  public:
-  explicit HdfsEnv(const std::string& /*fsname*/) {
+  explicit HdfsEnv(const std::string& fsname) {
     fprintf(stderr, "You have not build rocksdb with HDFS support\n");
     fprintf(stderr, "Please see hdfs/README for details\n");
     abort();
@@ -258,125 +258,112 @@ class HdfsEnv : public Env {
                                    unique_ptr<SequentialFile>* result,
                                    const EnvOptions& options) override;
 
-  virtual Status NewRandomAccessFile(const std::string& /*fname*/,
+  virtual Status NewRandomAccessFile(const std::string& fname,
-                                     unique_ptr<RandomAccessFile>* /*result*/,
+                                     unique_ptr<RandomAccessFile>* result,
-                                     const EnvOptions& /*options*/) override {
+                                     const EnvOptions& options) override {
     return notsup;
   }
 
-  virtual Status NewWritableFile(const std::string& /*fname*/,
+  virtual Status NewWritableFile(const std::string& fname,
-                                 unique_ptr<WritableFile>* /*result*/,
+                                 unique_ptr<WritableFile>* result,
-                                 const EnvOptions& /*options*/) override {
+                                 const EnvOptions& options) override {
     return notsup;
   }
 
-  virtual Status NewDirectory(const std::string& /*name*/,
+  virtual Status NewDirectory(const std::string& name,
-                              unique_ptr<Directory>* /*result*/) override {
+                              unique_ptr<Directory>* result) override {
     return notsup;
   }
 
-  virtual Status FileExists(const std::string& /*fname*/) override {
+  virtual Status FileExists(const std::string& fname) override {
     return notsup;
   }
 
-  virtual Status GetChildren(const std::string& /*path*/,
+  virtual Status GetChildren(const std::string& path,
-                             std::vector<std::string>* /*result*/) override {
+                             std::vector<std::string>* result) override {
     return notsup;
   }
 
-  virtual Status DeleteFile(const std::string& /*fname*/) override {
+  virtual Status DeleteFile(const std::string& fname) override {
     return notsup;
   }
 
-  virtual Status CreateDir(const std::string& /*name*/) override {
+  virtual Status CreateDir(const std::string& name) override { return notsup; }
-    return notsup;
-  }
 
-  virtual Status CreateDirIfMissing(const std::string& /*name*/) override {
+  virtual Status CreateDirIfMissing(const std::string& name) override {
     return notsup;
   }
 
-  virtual Status DeleteDir(const std::string& /*name*/) override {
+  virtual Status DeleteDir(const std::string& name) override { return notsup; }
-    return notsup;
-  }
 
-  virtual Status GetFileSize(const std::string& /*fname*/,
+  virtual Status GetFileSize(const std::string& fname,
-                             uint64_t* /*size*/) override {
+                             uint64_t* size) override {
     return notsup;
   }
 
-  virtual Status GetFileModificationTime(const std::string& /*fname*/,
+  virtual Status GetFileModificationTime(const std::string& fname,
-                                         uint64_t* /*time*/) override {
+                                         uint64_t* time) override {
     return notsup;
   }
 
-  virtual Status RenameFile(const std::string& /*src*/,
+  virtual Status RenameFile(const std::string& src,
-                            const std::string& /*target*/) override {
+                            const std::string& target) override {
     return notsup;
   }
 
-  virtual Status LinkFile(const std::string& /*src*/,
+  virtual Status LinkFile(const std::string& src,
-                          const std::string& /*target*/) override {
+                          const std::string& target) override {
     return notsup;
   }
 
-  virtual Status LockFile(const std::string& /*fname*/,
+  virtual Status LockFile(const std::string& fname, FileLock** lock) override {
-                          FileLock** /*lock*/) override {
     return notsup;
   }
 
-  virtual Status UnlockFile(FileLock* /*lock*/) override { return notsup; }
+  virtual Status UnlockFile(FileLock* lock) override { return notsup; }
 
-  virtual Status NewLogger(const std::string& /*fname*/,
+  virtual Status NewLogger(const std::string& fname,
-                           shared_ptr<Logger>* /*result*/) override {
+                           shared_ptr<Logger>* result) override {
     return notsup;
   }
 
-  virtual void Schedule(void (*/*function*/)(void* arg), void* /*arg*/,
+  virtual void Schedule(void (*function)(void* arg), void* arg,
-                        Priority /*pri*/ = LOW, void* /*tag*/ = nullptr,
+                        Priority pri = LOW, void* tag = nullptr,
-                        void (*/*unschedFunction*/)(void* arg) = 0) override {}
+                        void (*unschedFunction)(void* arg) = 0) override {}
 
-  virtual int UnSchedule(void* /*tag*/, Priority /*pri*/) override { return 0; }
+  virtual int UnSchedule(void* tag, Priority pri) override { return 0; }
 
-  virtual void StartThread(void (*/*function*/)(void* arg),
+  virtual void StartThread(void (*function)(void* arg), void* arg) override {}
-                           void* /*arg*/) override {}
 
   virtual void WaitForJoin() override {}
 
   virtual unsigned int GetThreadPoolQueueLen(
-      Priority /*pri*/ = LOW) const override {
+      Priority pri = LOW) const override {
     return 0;
   }
 
-  virtual Status GetTestDirectory(std::string* /*path*/) override {
+  virtual Status GetTestDirectory(std::string* path) override { return notsup; }
-    return notsup;
-  }
 
   virtual uint64_t NowMicros() override { return 0; }
 
-  virtual void SleepForMicroseconds(int /*micros*/) override {}
+  virtual void SleepForMicroseconds(int micros) override {}
 
-  virtual Status GetHostName(char* /*name*/, uint64_t /*len*/) override {
+  virtual Status GetHostName(char* name, uint64_t len) override {
     return notsup;
   }
 
-  virtual Status GetCurrentTime(int64_t* /*unix_time*/) override {
+  virtual Status GetCurrentTime(int64_t* unix_time) override { return notsup; }
-    return notsup;
-  }
 
-  virtual Status GetAbsolutePath(const std::string& /*db_path*/,
+  virtual Status GetAbsolutePath(const std::string& db_path,
-                                 std::string* /*outputpath*/) override {
+                                 std::string* outputpath) override {
     return notsup;
   }
 
-  virtual void SetBackgroundThreads(int /*number*/,
+  virtual void SetBackgroundThreads(int number, Priority pri = LOW) override {}
-                                    Priority /*pri*/ = LOW) override {}
+  virtual int GetBackgroundThreads(Priority pri = LOW) override { return 0; }
-  virtual int GetBackgroundThreads(Priority /*pri*/ = LOW) override {
+  virtual void IncBackgroundThreadsIfNeeded(int number, Priority pri) override {
-    return 0;
   }
-  virtual void IncBackgroundThreadsIfNeeded(int /*number*/,
+  virtual std::string TimeToString(uint64_t number) override { return ""; }
-                                            Priority /*pri*/) override {}
-  virtual std::string TimeToString(uint64_t /*number*/) override { return ""; }
 
   virtual uint64_t GetThreadID() const override {
     return 0;

include/rocksdb/cache.h

@@ -189,8 +189,7 @@ class Cache {
 
   // Mark the last inserted object as being a raw data block. This will be used
   // in tests. The default implementation does nothing.
-  virtual void TEST_mark_as_data_block(const Slice& /*key*/,
+  virtual void TEST_mark_as_data_block(const Slice& key, size_t charge) {}
-                                       size_t /*charge*/) {}
 
  private:
   // No copying allowed

include/rocksdb/compaction_filter.h

@@ -97,10 +97,8 @@ class CompactionFilter {
   // The last paragraph is not true if you set max_subcompactions to more than
   // 1. In that case, subcompaction from multiple threads may call a single
   // CompactionFilter concurrently.
-  virtual bool Filter(int /*level*/, const Slice& /*key*/,
+  virtual bool Filter(int level, const Slice& key, const Slice& existing_value,
-                      const Slice& /*existing_value*/,
+                      std::string* new_value, bool* value_changed) const {
-                      std::string* /*new_value*/,
-                      bool* /*value_changed*/) const {
     return false;
   }
 
@@ -113,8 +111,8 @@ class CompactionFilter {
   // may not realize there is a write conflict and may allow a Transaction to
   // Commit that should have failed.  Instead, it is better to implement any
   // Merge filtering inside the MergeOperator.
-  virtual bool FilterMergeOperand(int /*level*/, const Slice& /*key*/,
+  virtual bool FilterMergeOperand(int level, const Slice& key,
-                                  const Slice& /*operand*/) const {
+                                  const Slice& operand) const {
     return false;
   }
 
@@ -159,7 +157,7 @@ class CompactionFilter {
   // MergeOperator.
   virtual Decision FilterV2(int level, const Slice& key, ValueType value_type,
                             const Slice& existing_value, std::string* new_value,
-                            std::string* /*skip_until*/) const {
+                            std::string* skip_until) const {
     switch (value_type) {
       case ValueType::kValue: {
         bool value_changed = false;

include/rocksdb/db.h

@@ -855,7 +855,7 @@ class DB {
 
   // Flush the WAL memory buffer to the file. If sync is true, it calls SyncWAL
   // afterwards.
-  virtual Status FlushWAL(bool /*sync*/) {
+  virtual Status FlushWAL(bool sync) {
     return Status::NotSupported("FlushWAL not implemented");
   }
   // Sync the wal. Note that Write() followed by SyncWAL() is not exactly the

include/rocksdb/env.h

@@ -170,9 +170,9 @@ class Env {
   // returns non-OK.
   //
   // The returned file will only be accessed by one thread at a time.
-  virtual Status ReopenWritableFile(const std::string& /*fname*/,
+  virtual Status ReopenWritableFile(const std::string& fname,
-                                    unique_ptr<WritableFile>* /*result*/,
+                                    unique_ptr<WritableFile>* result,
-                                    const EnvOptions& /*options*/) {
+                                    const EnvOptions& options) {
     return Status::NotSupported();
   }
 
@@ -187,9 +187,9 @@ class Env {
   // *result and returns OK.  On failure returns non-OK.
   //
   // The returned file will only be accessed by one thread at a time.
-  virtual Status NewRandomRWFile(const std::string& /*fname*/,
+  virtual Status NewRandomRWFile(const std::string& fname,
-                                 unique_ptr<RandomRWFile>* /*result*/,
+                                 unique_ptr<RandomRWFile>* result,
-                                 const EnvOptions& /*options*/) {
+                                 const EnvOptions& options) {
     return Status::NotSupported("RandomRWFile is not implemented in this Env");
   }
 
@@ -257,8 +257,7 @@ class Env {
                             const std::string& target) = 0;
 
   // Hard Link file src to target.
-  virtual Status LinkFile(const std::string& /*src*/,
+  virtual Status LinkFile(const std::string& src, const std::string& target) {
-                          const std::string& /*target*/) {
     return Status::NotSupported("LinkFile is not supported for this Env");
   }
 
@@ -309,7 +308,7 @@ class Env {
 
   // Arrange to remove jobs for given arg from the queue_ if they are not
   // already scheduled. Caller is expected to have exclusive lock on arg.
-  virtual int UnSchedule(void* /*arg*/, Priority /*pri*/) { return 0; }
+  virtual int UnSchedule(void* arg, Priority pri) { return 0; }
 
   // Start a new thread, invoking "function(arg)" within the new thread.
   // When "function(arg)" returns, the thread will be destroyed.
@@ -319,7 +318,7 @@ class Env {
   virtual void WaitForJoin() {}
 
   // Get thread pool queue length for specific thread pool.
-  virtual unsigned int GetThreadPoolQueueLen(Priority /*pri*/ = LOW) const {
+  virtual unsigned int GetThreadPoolQueueLen(Priority pri = LOW) const {
     return 0;
   }
 
@@ -373,7 +372,7 @@ class Env {
   virtual void IncBackgroundThreadsIfNeeded(int number, Priority pri) = 0;
 
   // Lower IO priority for threads from the specified pool.
-  virtual void LowerThreadPoolIOPriority(Priority /*pool*/ = LOW) {}
+  virtual void LowerThreadPoolIOPriority(Priority pool = LOW) {}
 
   // Converts seconds-since-Jan-01-1970 to a printable string
   virtual std::string TimeToString(uint64_t time) = 0;
@@ -417,7 +416,7 @@ class Env {
       const ImmutableDBOptions& db_options) const;
 
   // Returns the status of all threads that belong to the current Env.
-  virtual Status GetThreadList(std::vector<ThreadStatus>* /*thread_list*/) {
+  virtual Status GetThreadList(std::vector<ThreadStatus>* thread_list) {
     return Status::NotSupported("Not supported.");
   }
 
@@ -483,14 +482,14 @@ class SequentialFile {
   // Remove any kind of caching of data from the offset to offset+length
   // of this file. If the length is 0, then it refers to the end of file.
   // If the system is not caching the file contents, then this is a noop.
-  virtual Status InvalidateCache(size_t /*offset*/, size_t /*length*/) {
+  virtual Status InvalidateCache(size_t offset, size_t length) {
     return Status::NotSupported("InvalidateCache not supported.");
   }
 
   // Positioned Read for direct I/O
   // If Direct I/O enabled, offset, n, and scratch should be properly aligned
-  virtual Status PositionedRead(uint64_t /*offset*/, size_t /*n*/,
+  virtual Status PositionedRead(uint64_t offset, size_t n, Slice* result,
-                                Slice* /*result*/, char* /*scratch*/) {
+                                char* scratch) {
     return Status::NotSupported();
   }
 };
@@ -516,7 +515,7 @@ class RandomAccessFile {
                       char* scratch) const = 0;
 
   // Readahead the file starting from offset by n bytes for caching.
-  virtual Status Prefetch(uint64_t /*offset*/, size_t /*n*/) {
+  virtual Status Prefetch(uint64_t offset, size_t n) {
     return Status::OK();
   }
 
@@ -535,14 +534,14 @@ class RandomAccessFile {
   // a single varint.
   //
   // Note: these IDs are only valid for the duration of the process.
-  virtual size_t GetUniqueId(char* /*id*/, size_t /*max_size*/) const {
+  virtual size_t GetUniqueId(char* id, size_t max_size) const {
     return 0; // Default implementation to prevent issues with backwards
               // compatibility.
   };
 
   enum AccessPattern { NORMAL, RANDOM, SEQUENTIAL, WILLNEED, DONTNEED };
 
-  virtual void Hint(AccessPattern /*pattern*/) {}
+  virtual void Hint(AccessPattern pattern) {}
 
   // Indicates the upper layers if the current RandomAccessFile implementation
   // uses direct IO.
@@ -555,7 +554,7 @@ class RandomAccessFile {
   // Remove any kind of caching of data from the offset to offset+length
   // of this file. If the length is 0, then it refers to the end of file.
   // If the system is not caching the file contents, then this is a noop.
-  virtual Status InvalidateCache(size_t /*offset*/, size_t /*length*/) {
+  virtual Status InvalidateCache(size_t offset, size_t length) {
     return Status::NotSupported("InvalidateCache not supported.");
   }
 };
@@ -605,7 +604,9 @@ class WritableFile {
   // before closing. It is not always possible to keep track of the file
   // size due to whole pages writes. The behavior is undefined if called
   // with other writes to follow.
-  virtual Status Truncate(uint64_t /*size*/) { return Status::OK(); }
+  virtual Status Truncate(uint64_t size) {
+    return Status::OK();
+  }
   virtual Status Close() = 0;
   virtual Status Flush() = 0;
   virtual Status Sync() = 0; // sync data
@@ -667,7 +668,7 @@ class WritableFile {
   }
 
   // For documentation, refer to RandomAccessFile::GetUniqueId()
-  virtual size_t GetUniqueId(char* /*id*/, size_t /*max_size*/) const {
+  virtual size_t GetUniqueId(char* id, size_t max_size) const {
     return 0; // Default implementation to prevent issues with backwards
   }
 
@@ -675,7 +676,7 @@ class WritableFile {
   // of this file. If the length is 0, then it refers to the end of file.
   // If the system is not caching the file contents, then this is a noop.
   // This call has no effect on dirty pages in the cache.
-  virtual Status InvalidateCache(size_t /*offset*/, size_t /*length*/) {
+  virtual Status InvalidateCache(size_t offset, size_t length) {
     return Status::NotSupported("InvalidateCache not supported.");
   }
 
@@ -685,9 +686,7 @@ class WritableFile {
   // This asks the OS to initiate flushing the cached data to disk,
   // without waiting for completion.
   // Default implementation does nothing.
-  virtual Status RangeSync(uint64_t /*offset*/, uint64_t /*nbytes*/) {
+  virtual Status RangeSync(uint64_t offset, uint64_t nbytes) { return Status::OK(); }
-    return Status::OK();
-  }
 
   // PrepareWrite performs any necessary preparation for a write
   // before the write actually occurs.  This allows for pre-allocation
@@ -714,7 +713,7 @@ class WritableFile {
   }
 
   // Pre-allocates space for a file.
-  virtual Status Allocate(uint64_t /*offset*/, uint64_t /*len*/) {
+  virtual Status Allocate(uint64_t offset, uint64_t len) {
     return Status::OK();
   }
 

include/rocksdb/filter_policy.h

@@ -45,7 +45,7 @@ class FilterBitsBuilder {
   virtual Slice Finish(std::unique_ptr<const char[]>* buf) = 0;
 
   // Calculate num of entries fit into a space.
-  virtual int CalculateNumEntry(const uint32_t /*space*/) {
+  virtual int CalculateNumEntry(const uint32_t space) {
 #ifndef ROCKSDB_LITE
     throw std::runtime_error("CalculateNumEntry not Implemented");
 #else
@@ -114,8 +114,7 @@ class FilterPolicy {
   // Get the FilterBitsReader, which is ONLY used for full filter block
   // It contains interface to tell if key can be in filter
   // The input slice should NOT be deleted by FilterPolicy
-  virtual FilterBitsReader* GetFilterBitsReader(
+  virtual FilterBitsReader* GetFilterBitsReader(const Slice& contents) const {
-      const Slice& /*contents*/) const {
     return nullptr;
   }
 };

include/rocksdb/iterator.h

@@ -51,7 +51,7 @@ class Iterator : public Cleanable {
   // Position at the last key in the source that at or before target
   // The iterator is Valid() after this call iff the source contains
   // an entry that comes at or before target.
-  virtual void SeekForPrev(const Slice& /*target*/) {}
+  virtual void SeekForPrev(const Slice& target) {}
 
   // Moves to the next entry in the source.  After this call, Valid() is
   // true iff the iterator was not positioned at the last entry in the source.

include/rocksdb/listener.h

@@ -345,8 +345,8 @@ class EventListener {
   // returns.  Otherwise, RocksDB may be blocked.
   // @param handle is a pointer to the column family handle to be deleted
   // which will become a dangling pointer after the deletion.
-  virtual void OnColumnFamilyHandleDeletionStarted(
+  virtual void OnColumnFamilyHandleDeletionStarted(ColumnFamilyHandle* handle) {
-      ColumnFamilyHandle* /*handle*/) {}
+  }
 
   // A call-back function for RocksDB which will be called after an external
   // file is ingested using IngestExternalFile.

include/rocksdb/memtablerep.h

@@ -89,14 +89,14 @@ class MemTableRep {
   //
   // Currently only skip-list based memtable implement the interface. Other
   // implementations will fallback to Insert() by default.
-  virtual void InsertWithHint(KeyHandle handle, void** /*hint*/) {
+  virtual void InsertWithHint(KeyHandle handle, void** hint) {
     // Ignore the hint by default.
     Insert(handle);
   }
 
   // Like Insert(handle), but may be called concurrent with other calls
   // to InsertConcurrently for other handles
-  virtual void InsertConcurrently(KeyHandle /*handle*/) {
+  virtual void InsertConcurrently(KeyHandle handle) {
 #ifndef ROCKSDB_LITE
     throw std::runtime_error("concurrent insert not supported");
 #else
@@ -128,8 +128,8 @@ class MemTableRep {
   virtual void Get(const LookupKey& k, void* callback_args,
                    bool (*callback_func)(void* arg, const char* entry));
 
-  virtual uint64_t ApproximateNumEntries(const Slice& /*start_ikey*/,
+  virtual uint64_t ApproximateNumEntries(const Slice& start_ikey,
-                                         const Slice& /*end_key*/) {
+                                         const Slice& end_key) {
     return 0;
   }
 

include/rocksdb/merge_operator.h

@@ -66,9 +66,11 @@ class MergeOperator {
   // internal corruption. This will be treated as an error by the library.
   //
   // Also make use of the *logger for error messages.
-  virtual bool FullMerge(const Slice& /*key*/, const Slice* /*existing_value*/,
+  virtual bool FullMerge(const Slice& key,
-                         const std::deque<std::string>& /*operand_list*/,
+                         const Slice* existing_value,
-                         std::string* /*new_value*/, Logger* /*logger*/) const {
+                         const std::deque<std::string>& operand_list,
+                         std::string* new_value,
+                         Logger* logger) const {
     // deprecated, please use FullMergeV2()
     assert(false);
     return false;
@@ -143,10 +145,9 @@ class MergeOperator {
   // If there is corruption in the data, handle it in the FullMergeV2() function
   // and return false there.  The default implementation of PartialMerge will
   // always return false.
-  virtual bool PartialMerge(const Slice& /*key*/, const Slice& /*left_operand*/,
+  virtual bool PartialMerge(const Slice& key, const Slice& left_operand,
-                            const Slice& /*right_operand*/,
+                            const Slice& right_operand, std::string* new_value,
-                            std::string* /*new_value*/,
+                            Logger* logger) const {
-                            Logger* /*logger*/) const {
     return false;
   }
 

include/rocksdb/rate_limiter.h

@@ -45,7 +45,7 @@ class RateLimiter {
   // Request for token for bytes. If this request can not be satisfied, the call
   // is blocked. Caller is responsible to make sure
   // bytes <= GetSingleBurstBytes()
-  virtual void Request(const int64_t /*bytes*/, const Env::IOPriority /*pri*/) {
+  virtual void Request(const int64_t bytes, const Env::IOPriority pri) {
     assert(false);
   }
 

include/rocksdb/slice.h

@@ -173,7 +173,7 @@ class PinnableSlice : public Slice, public Cleanable {
     }
   }
 
-  void remove_prefix(size_t /*n*/) {
+  void remove_prefix(size_t n) {
     assert(0);  // Not implemented
   }
 

include/rocksdb/slice_transform.h

@@ -58,7 +58,7 @@ class SliceTransform {
   virtual bool InDomain(const Slice& key) const = 0;
 
   // This is currently not used and remains here for backward compatibility.
-  virtual bool InRange(const Slice& /*dst*/) const { return false; }
+  virtual bool InRange(const Slice& dst) const { return false; }
 
   // Transform(s)=Transform(`prefix`) for any s with `prefix` as a prefix.
   //
@@ -83,7 +83,7 @@ class SliceTransform {
   //    "abcd,e", the file can be filtered out and the key will be invisible.
   //
   // i.e., an implementation always returning false is safe.
-  virtual bool SameResultWhenAppended(const Slice& /*prefix*/) const {
+  virtual bool SameResultWhenAppended(const Slice& prefix) const {
     return false;
   }
 };

include/rocksdb/statistics.h

@@ -445,7 +445,7 @@ class Statistics {
   virtual uint64_t getTickerCount(uint32_t tickerType) const = 0;
   virtual void histogramData(uint32_t type,
                              HistogramData* const data) const = 0;
-  virtual std::string getHistogramString(uint32_t /*type*/) const { return ""; }
+  virtual std::string getHistogramString(uint32_t type) const { return ""; }
   virtual void recordTick(uint32_t tickerType, uint64_t count = 0) = 0;
   virtual void setTickerCount(uint32_t tickerType, uint64_t count) = 0;
   virtual uint64_t getAndResetTickerCount(uint32_t tickerType) = 0;

include/rocksdb/utilities/geo_db.h

@@ -80,7 +80,7 @@ class GeoDB : public StackableDB {
   // GeoDB owns the pointer `DB* db` now. You should not delete it or
   // use it after the invocation of GeoDB
   // GeoDB(DB* db, const GeoDBOptions& options) : StackableDB(db) {}
-  GeoDB(DB* db, const GeoDBOptions& /*options*/) : StackableDB(db) {}
+  GeoDB(DB* db, const GeoDBOptions& options) : StackableDB(db) {}
   virtual ~GeoDB() {}
 
   // Insert a new object into the location database. The object is

include/rocksdb/utilities/optimistic_transaction_db.h

@@ -62,7 +62,7 @@ class OptimisticTransactionDB {
 
  protected:
   // To Create an OptimisticTransactionDB, call Open()
-  explicit OptimisticTransactionDB(DB* /*db*/) {}
+  explicit OptimisticTransactionDB(DB* db) {}
   OptimisticTransactionDB() {}
 
  private:

include/rocksdb/utilities/transaction.h

@@ -402,8 +402,8 @@ class Transaction {
 
   virtual bool IsDeadlockDetect() const { return false; }
 
-  virtual std::vector<TransactionID> GetWaitingTxns(
+  virtual std::vector<TransactionID> GetWaitingTxns(uint32_t* column_family_id,
-      uint32_t* /*column_family_id*/, std::string* /*key*/) const {
+                                                    std::string* key) const {
     assert(false);
     return std::vector<TransactionID>();
   }
@@ -423,7 +423,7 @@ class Transaction {
   void SetState(TransactionState state) { txn_state_ = state; }
 
  protected:
-  explicit Transaction(const TransactionDB* /*db*/) {}
+  explicit Transaction(const TransactionDB* db) {}
   Transaction() {}
 
   // the log in which the prepared section for this txn resides

include/rocksdb/wal_filter.h

@@ -44,8 +44,8 @@ class WalFilter {
   // @params cf_name_id_map   column_family_name to column_family_id map
 
   virtual 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*/) {}
+    const std::map<std::string, uint32_t>& cf_name_id_map) {}
 
   // LogRecord is invoked for each log record encountered for all the logs
   // during replay on logs on recovery. This method can be used to:
@@ -75,9 +75,11 @@ class WalFilter {
   // @returns               Processing option for the current record.
   //                        Please see WalProcessingOption enum above for
   //                        details.
-  virtual WalProcessingOption LogRecordFound(
+  virtual 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, bool* batch_changed) {
+                                        const WriteBatch& batch,
+                                        WriteBatch* new_batch,
+                                        bool* batch_changed) {
     // Default implementation falls back to older function for compatibility
     return LogRecord(batch, new_batch, batch_changed);
   }
@@ -85,9 +87,9 @@ class WalFilter {
   // Please see the comments for LogRecord above. This function is for 
   // compatibility only and contains a subset of parameters. 
   // New code should use the function above.
-  virtual WalProcessingOption LogRecord(const WriteBatch& /*batch*/,
+  virtual WalProcessingOption LogRecord(const WriteBatch& batch,
-                                        WriteBatch* /*new_batch*/,
+                                        WriteBatch* new_batch,
-                                        bool* /*batch_changed*/) const {
+                                        bool* batch_changed) const {
     return WalProcessingOption::kContinueProcessing;
   }
 

include/rocksdb/write_batch.h

@@ -217,9 +217,8 @@ class WriteBatch : public WriteBatchBase {
     }
     virtual void SingleDelete(const Slice& /*key*/) {}
 
-    virtual Status DeleteRangeCF(uint32_t /*column_family_id*/,
+    virtual Status DeleteRangeCF(uint32_t column_family_id,
-                                 const Slice& /*begin_key*/,
+                                 const Slice& begin_key, const Slice& end_key) {
-                                 const Slice& /*end_key*/) {
       return Status::InvalidArgument("DeleteRangeCF not implemented");
     }
 
@@ -241,16 +240,16 @@ class WriteBatch : public WriteBatchBase {
       return Status::InvalidArgument("MarkBeginPrepare() handler not defined.");
     }
 
-    virtual Status MarkEndPrepare(const Slice& /*xid*/) {
+    virtual Status MarkEndPrepare(const Slice& xid) {
       return Status::InvalidArgument("MarkEndPrepare() handler not defined.");
     }
 
-    virtual Status MarkRollback(const Slice& /*xid*/) {
+    virtual Status MarkRollback(const Slice& xid) {
       return Status::InvalidArgument(
           "MarkRollbackPrepare() handler not defined.");
     }
 
-    virtual Status MarkCommit(const Slice& /*xid*/) {
+    virtual Status MarkCommit(const Slice& xid) {
       return Status::InvalidArgument("MarkCommit() handler not defined.");
     }
 

memtable/hash_cuckoo_rep.cc

@@ -597,8 +597,8 @@ void HashCuckooRep::Iterator::Seek(const Slice& user_key,
 }
 
 // Retreat to the last entry with a key <= target
-void HashCuckooRep::Iterator::SeekForPrev(const Slice& /*user_key*/,
+void HashCuckooRep::Iterator::SeekForPrev(const Slice& user_key,
-                                          const char* /*memtable_key*/) {
+                                          const char* memtable_key) {
   assert(false);
 }
 
@@ -623,7 +623,7 @@ void HashCuckooRep::Iterator::SeekToLast() {
 
 MemTableRep* HashCuckooRepFactory::CreateMemTableRep(
     const MemTableRep::KeyComparator& compare, Allocator* allocator,
-    const SliceTransform* /*transform*/, Logger* /*logger*/) {
+    const SliceTransform* transform, Logger* logger) {
   // The estimated average fullness.  The write performance of any close hash
   // degrades as the fullness of the mem-table increases.  Setting kFullness
   // to a value around 0.7 can better avoid write performance degradation while

memtable/hash_linklist_rep.cc

@@ -362,14 +362,14 @@ class HashLinkListRep : public MemTableRep {
 
     // Advance to the first entry with a key >= target
     virtual 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*/,
+    virtual 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);
@@ -483,10 +483,10 @@ class HashLinkListRep : public MemTableRep {
     }
     virtual void Next() override {}
     virtual void Prev() override {}
-    virtual void Seek(const Slice& /*user_key*/,
+    virtual void Seek(const Slice& user_key,
-                      const char* /*memtable_key*/) override {}
+                      const char* memtable_key) override {}
-    virtual void SeekForPrev(const Slice& /*user_key*/,
+    virtual void SeekForPrev(const Slice& user_key,
-                             const char* /*memtable_key*/) override {}
+                             const char* memtable_key) override {}
     virtual void SeekToFirst() override {}
     virtual void SeekToLast() override {}
 

memtable/hash_skiplist_rep.cc

@@ -131,8 +131,8 @@ class HashSkipListRep : public MemTableRep {
     }
 
     // Retreat to the last entry with a key <= target
-    virtual void SeekForPrev(const Slice& /*internal_key*/,
+    virtual void SeekForPrev(const Slice& internal_key,
-                             const char* /*memtable_key*/) override {
+                             const char* memtable_key) override {
       // not supported
       assert(false);
     }
@@ -219,10 +219,10 @@ class HashSkipListRep : public MemTableRep {
     }
     virtual void Next() override {}
     virtual void Prev() override {}
-    virtual void Seek(const Slice& /*internal_key*/,
+    virtual void Seek(const Slice& internal_key,
-                      const char* /*memtable_key*/) override {}
+                      const char* memtable_key) override {}
-    virtual void SeekForPrev(const Slice& /*internal_key*/,
+    virtual void SeekForPrev(const Slice& internal_key,
-                             const char* /*memtable_key*/) override {}
+                             const char* memtable_key) override {}
     virtual void SeekToFirst() override {}
     virtual void SeekToLast() override {}
 
@@ -335,7 +335,7 @@ MemTableRep::Iterator* HashSkipListRep::GetDynamicPrefixIterator(Arena* arena) {
 
 MemTableRep* HashSkipListRepFactory::CreateMemTableRep(
     const MemTableRep::KeyComparator& compare, Allocator* allocator,
-    const SliceTransform* transform, Logger* /*logger*/) {
+    const SliceTransform* transform, Logger* logger) {
   return new HashSkipListRep(compare, allocator, transform, bucket_count_,
                              skiplist_height_, skiplist_branching_factor_);
 }

memtable/skiplistrep.cc

@@ -270,7 +270,7 @@ public:
 
 MemTableRep* SkipListFactory::CreateMemTableRep(
     const MemTableRep::KeyComparator& compare, Allocator* allocator,
-    const SliceTransform* transform, Logger* /*logger*/) {
+    const SliceTransform* transform, Logger* logger) {
   return new SkipListRep(compare, allocator, transform, lookahead_);
 }
 

memtable/vectorrep.cc

@@ -227,8 +227,8 @@ void VectorRep::Iterator::Seek(const Slice& user_key,
 }
 
 // Advance to the first entry with a key <= target
-void VectorRep::Iterator::SeekForPrev(const Slice& /*user_key*/,
+void VectorRep::Iterator::SeekForPrev(const Slice& user_key,
-                                      const char* /*memtable_key*/) {
+                                      const char* memtable_key) {
   assert(false);
 }
 
@@ -296,7 +296,7 @@ MemTableRep::Iterator* VectorRep::GetIterator(Arena* arena) {
 
 MemTableRep* VectorRepFactory::CreateMemTableRep(
     const MemTableRep::KeyComparator& compare, Allocator* allocator,
-    const SliceTransform*, Logger* /*logger*/) {
+    const SliceTransform*, Logger* logger) {
   return new VectorRep(compare, allocator, count_);
 }
 } // namespace rocksdb

options/options_helper.cc

@@ -1129,7 +1129,7 @@ Status GetPlainTableOptionsFromMap(
     const PlainTableOptions& table_options,
     const std::unordered_map<std::string, std::string>& opts_map,
     PlainTableOptions* new_table_options, bool input_strings_escaped,
-    bool /*ignore_unknown_options*/) {
+    bool ignore_unknown_options) {
   assert(new_table_options);
   *new_table_options = table_options;
   for (const auto& o : opts_map) {

options/options_parser.cc

@@ -689,7 +689,7 @@ Status RocksDBOptionsParser::VerifyRocksDBOptionsFromFile(
 
 Status RocksDBOptionsParser::VerifyDBOptions(
     const DBOptions& base_opt, const DBOptions& persisted_opt,
-    const std::unordered_map<std::string, std::string>* /*opt_map*/,
+    const std::unordered_map<std::string, std::string>* opt_map,
     OptionsSanityCheckLevel sanity_check_level) {
   for (auto pair : db_options_type_info) {
     if (pair.second.verification == OptionVerificationType::kDeprecated) {

port/port_posix.cc

@@ -35,7 +35,7 @@ static int PthreadCall(const char* label, int result) {
   return result;
 }
 
-Mutex::Mutex(bool /*adaptive*/) {
+Mutex::Mutex(bool adaptive) {
 #ifdef ROCKSDB_PTHREAD_ADAPTIVE_MUTEX
   if (!adaptive) {
     PthreadCall("init mutex", pthread_mutex_init(&mu_, nullptr));

port/stack_trace.cc

@@ -13,7 +13,7 @@
 namespace rocksdb {
 namespace port {
 void InstallStackTraceHandler() {}
-void PrintStack(int /*first_frames_to_skip*/) {}
+void PrintStack(int first_frames_to_skip) {}
 }  // namespace port
 }  // namespace rocksdb