diff --git a/CMakeLists.txt b/CMakeLists.txt
index 329440897..bbaefd222 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -59,8 +59,8 @@ add_custom_command(OUTPUT ${BUILD_VERSION_CC}
 add_custom_target(GenerateBuildVersion DEPENDS ${BUILD_VERSION_CC})
 
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /Zi /nologo  /EHsc /GS /Gd /GR /GF /fp:precise /Zc:wchar_t /Zc:forScope /errorReport:queue")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /FC /d2Zi+ /W3 /WX /wd4127 /wd4267 /wd4800 /wd4996")
 
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /FC /d2Zi+ /W3 /WX /wd4127 /wd4244 /wd4800 /wd4996")
 
 # Used to run CI build and tests so we can run faster
 set(OPTIMIZE_DEBUG_DEFAULT 0)        # Debug build is unoptimized by default use -DOPTDBG=1 to optimize
@@ -244,7 +244,7 @@ set(SOURCES
         utilities/document/document_db.cc
         utilities/document/json_document.cc
         utilities/document/json_document_builder.cc
-	utilities/env_mirror.cc
+        utilities/env_mirror.cc
         utilities/flashcache/flashcache.cc
         utilities/geodb/geodb_impl.cc
         utilities/leveldb_options/leveldb_options.cc
diff --git a/db/compaction.cc b/db/compaction.cc
index 43b0b37d7..7d3950530 100644
--- a/db/compaction.cc
+++ b/db/compaction.cc
@@ -428,7 +428,7 @@ uint64_t Compaction::OutputFilePreallocationSize() {
   }
   // Over-estimate slightly so we don't end up just barely crossing
   // the threshold
-  return preallocation_size * 1.1;
+  return preallocation_size + (preallocation_size / 10);
 }
 
 std::unique_ptr<CompactionFilter> Compaction::CreateCompactionFilter() const {
diff --git a/db/compaction_job.cc b/db/compaction_job.cc
index 4806eff7e..9e0cc6ff9 100644
--- a/db/compaction_job.cc
+++ b/db/compaction_job.cc
@@ -411,9 +411,12 @@ void CompactionJob::GenSubcompactionBoundaries() {
 
   // Group the ranges into subcompactions
   const double min_file_fill_percent = 4.0 / 5;
-  uint64_t max_output_files = std::ceil(
-      sum / min_file_fill_percent /
-      cfd->GetCurrentMutableCFOptions()->MaxFileSizeForLevel(out_lvl));
+  uint64_t max_output_files = 
+    static_cast<uint64_t>(
+        std::ceil(
+          sum / min_file_fill_percent /
+          cfd->GetCurrentMutableCFOptions()->MaxFileSizeForLevel(out_lvl))
+          );
   uint64_t subcompactions =
       std::min({static_cast<uint64_t>(ranges.size()),
                 static_cast<uint64_t>(db_options_.max_subcompactions),
diff --git a/db/compaction_job_stats_test.cc b/db/compaction_job_stats_test.cc
index c7d8eb821..14a7b9b4b 100644
--- a/db/compaction_job_stats_test.cc
+++ b/db/compaction_job_stats_test.cc
@@ -551,8 +551,8 @@ uint64_t EstimatedFileSize(
   const size_t kFooterSize = 512;
 
   uint64_t data_size =
-      num_records * (key_size + value_size * compression_ratio +
-                     kPerKeyOverhead);
+      static_cast<uint64_t>(num_records * (key_size + 
+         value_size * compression_ratio + kPerKeyOverhead));
 
   return data_size + kFooterSize
          + num_records * bloom_bits_per_key / 8      // filter block
diff --git a/db/corruption_test.cc b/db/corruption_test.cc
index 475b1bb55..66dc21c12 100644
--- a/db/corruption_test.cc
+++ b/db/corruption_test.cc
@@ -11,6 +11,7 @@
 
 #include "rocksdb/db.h"
 
+#include <inttypes.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <sys/stat.h>
@@ -104,8 +105,8 @@ class CorruptionTest : public testing::Test {
   }
 
   void Check(int min_expected, int max_expected) {
-    unsigned int next_expected = 0;
-    int missed = 0;
+    uint64_t next_expected = 0;
+    uint64_t missed = 0;
     int bad_keys = 0;
     int bad_values = 0;
     int correct = 0;
@@ -126,7 +127,7 @@ class CorruptionTest : public testing::Test {
         continue;
       }
       missed += (key - next_expected);
-      next_expected = static_cast<unsigned int>(key + 1);
+      next_expected = key + 1;
       if (iter->value() != Value(static_cast<int>(key), &value_space)) {
         bad_values++;
       } else {
@@ -136,8 +137,9 @@ class CorruptionTest : public testing::Test {
     delete iter;
 
     fprintf(stderr,
-            "expected=%d..%d; got=%d; bad_keys=%d; bad_values=%d; missed=%d\n",
-            min_expected, max_expected, correct, bad_keys, bad_values, missed);
+      "expected=%d..%d; got=%d; bad_keys=%d; bad_values=%d; missed=%llu\n",
+            min_expected, max_expected, correct, bad_keys, bad_values,
+            static_cast<unsigned long long>(missed));
     ASSERT_LE(min_expected, correct);
     ASSERT_GE(max_expected, correct);
   }
diff --git a/db/db_bench.cc b/db/db_bench.cc
index cb3d13bef..4bcab1446 100644
--- a/db/db_bench.cc
+++ b/db/db_bench.cc
@@ -1194,15 +1194,15 @@ static std::unordered_map<OperationType, std::string, std::hash<unsigned char>>
 class Stats {
  private:
   int id_;
-  double start_;
-  double finish_;
+  uint64_t start_;
+  uint64_t finish_;
   double seconds_;
-  int64_t done_;
-  int64_t last_report_done_;
-  int64_t next_report_;
-  int64_t bytes_;
-  double last_op_finish_;
-  double last_report_finish_;
+  uint64_t done_;
+  uint64_t last_report_done_;
+  uint64_t next_report_;
+  uint64_t bytes_;
+  uint64_t last_op_finish_;
+  uint64_t last_report_finish_;
   std::unordered_map<OperationType, HistogramImpl,
                      std::hash<unsigned char>> hist_;
   std::string message_;
@@ -1304,8 +1304,8 @@ class Stats {
       reporter_agent_->ReportFinishedOps(num_ops);
     }
     if (FLAGS_histogram) {
-      double now = FLAGS_env->NowMicros();
-      double micros = now - last_op_finish_;
+      uint64_t now = FLAGS_env->NowMicros();
+      uint64_t micros = now - last_op_finish_;
 
       if (hist_.find(op_type) == hist_.end())
       {
@@ -1315,7 +1315,7 @@ class Stats {
       hist_[op_type].Add(micros);
 
       if (micros > 20000 && !FLAGS_stats_interval) {
-        fprintf(stderr, "long op: %.1f micros%30s\r", micros, "");
+        fprintf(stderr, "long op: %" PRIu64 " micros%30s\r", micros, "");
         fflush(stderr);
       }
       last_op_finish_ = now;
@@ -1333,7 +1333,7 @@ class Stats {
         else                            next_report_ += 100000;
         fprintf(stderr, "... finished %" PRIu64 " ops%30s\r", done_, "");
       } else {
-        double now = FLAGS_env->NowMicros();
+        uint64_t now = FLAGS_env->NowMicros();
         int64_t usecs_since_last = now - last_report_finish_;
 
         // Determine whether to print status where interval is either
@@ -1349,7 +1349,7 @@ class Stats {
           fprintf(stderr,
                   "%s ... thread %d: (%" PRIu64 ",%" PRIu64 ") ops and "
                   "(%.1f,%.1f) ops/second in (%.6f,%.6f) seconds\n",
-                  FLAGS_env->TimeToString((uint64_t) now/1000000).c_str(),
+                  FLAGS_env->TimeToString(now/1000000).c_str(),
                   id_,
                   done_ - last_report_done_, done_,
                   (done_ - last_report_done_) /
@@ -1503,7 +1503,7 @@ struct ThreadState {
 
 class Duration {
  public:
-  Duration(int max_seconds, int64_t max_ops, int64_t ops_per_stage = 0) {
+  Duration(uint64_t max_seconds, int64_t max_ops, int64_t ops_per_stage = 0) {
     max_seconds_ = max_seconds;
     max_ops_= max_ops;
     ops_per_stage_ = (ops_per_stage > 0) ? ops_per_stage : max_ops;
@@ -1520,8 +1520,8 @@ class Duration {
     if (max_seconds_) {
       // Recheck every appx 1000 ops (exact iff increment is factor of 1000)
       if ((ops_/1000) != ((ops_-increment)/1000)) {
-        double now = FLAGS_env->NowMicros();
-        return ((now - start_at_) / 1000000.0) >= max_seconds_;
+        uint64_t now = FLAGS_env->NowMicros();
+        return ((now - start_at_) / 1000000) >= max_seconds_;
       } else {
         return false;
       }
@@ -1531,11 +1531,11 @@ class Duration {
   }
 
  private:
-  int max_seconds_;
+  uint64_t max_seconds_;
   int64_t max_ops_;
   int64_t ops_per_stage_;
   int64_t ops_;
-  double start_at_;
+  uint64_t start_at_;
 };
 
 class Benchmark {
@@ -3214,6 +3214,7 @@ class Benchmark {
     if (thread->tid > 0) {
       ReadRandom(thread);
     } else {
+      BGWriter(thread, kPut);
       BGWriter(thread, kWrite);
     }
   }
@@ -3229,7 +3230,7 @@ class Benchmark {
   void BGWriter(ThreadState* thread, enum OperationType write_merge) {
     // Special thread that keeps writing until other threads are done.
     RandomGenerator gen;
-    double last = FLAGS_env->NowMicros();
+    uint64_t last = FLAGS_env->NowMicros();
     int writes_per_second_by_10 = 0;
     int num_writes = 0;
     int64_t bytes = 0;
@@ -3274,14 +3275,14 @@ class Benchmark {
 
       ++num_writes;
       if (writes_per_second_by_10 && num_writes >= writes_per_second_by_10) {
-        double now = FLAGS_env->NowMicros();
-        double usecs_since_last = now - last;
+        uint64_t now = FLAGS_env->NowMicros();
+        uint64_t usecs_since_last = now - last;
 
         num_writes = 0;
         last = now;
 
-        if (usecs_since_last < 100000.0) {
-          FLAGS_env->SleepForMicroseconds(100000.0 - usecs_since_last);
+        if (usecs_since_last < 100000) {
+          FLAGS_env->SleepForMicroseconds(static_cast<int>(100000 - usecs_since_last));
           last = FLAGS_env->NowMicros();
         }
       }
diff --git a/db/db_impl.cc b/db/db_impl.cc
index 144210412..125c5711c 100644
--- a/db/db_impl.cc
+++ b/db/db_impl.cc
@@ -4315,8 +4315,9 @@ Status DBImpl::SwitchMemtable(ColumnFamilyData* cfd, WriteContext* context) {
       if (s.ok()) {
         // Our final size should be less than write_buffer_size
         // (compression, etc) but err on the side of caution.
-        lfile->SetPreallocationBlockSize(1.1 *
-                                         mutable_cf_options.write_buffer_size);
+        lfile->SetPreallocationBlockSize(
+            mutable_cf_options.write_buffer_size / 10 +
+            mutable_cf_options.write_buffer_size);
         unique_ptr<WritableFileWriter> file_writer(
             new WritableFileWriter(std::move(lfile), opt_env_opt));
         new_log = new log::Writer(std::move(file_writer), new_log_number,
@@ -4993,7 +4994,7 @@ Status DB::Open(const DBOptions& db_options, const std::string& dbname,
                         LogFileName(impl->db_options_.wal_dir, new_log_number),
                         &lfile, opt_env_options);
     if (s.ok()) {
-      lfile->SetPreallocationBlockSize(1.1 * max_write_buffer_size);
+      lfile->SetPreallocationBlockSize((max_write_buffer_size / 10) + max_write_buffer_size);
       impl->logfile_number_ = new_log_number;
       unique_ptr<WritableFileWriter> file_writer(
           new WritableFileWriter(std::move(lfile), opt_env_options));
diff --git a/db/db_test.cc b/db/db_test.cc
index 8364f64cb..699861806 100644
--- a/db/db_test.cc
+++ b/db/db_test.cc
@@ -73,7 +73,7 @@
 
 namespace rocksdb {
 
-static long TestGetTickerCount(const Options& options, Tickers ticker_type) {
+static uint64_t TestGetTickerCount(const Options& options, Tickers ticker_type) {
   return options.statistics->getTickerCount(ticker_type);
 }
 
@@ -1231,8 +1231,8 @@ TEST_F(DBTest, KeyMayExist) {
     ASSERT_OK(Flush(1));
     value.clear();
 
-    long numopen = TestGetTickerCount(options, NO_FILE_OPENS);
-    long cache_added = TestGetTickerCount(options, BLOCK_CACHE_ADD);
+    uint64_t numopen = TestGetTickerCount(options, NO_FILE_OPENS);
+    uint64_t cache_added = TestGetTickerCount(options, BLOCK_CACHE_ADD);
     ASSERT_TRUE(
         db_->KeyMayExist(ropts, handles_[1], "a", &value, &value_found));
     ASSERT_TRUE(!value_found);
@@ -1300,8 +1300,8 @@ TEST_F(DBTest, NonBlockingIteration) {
 
     // verify that a non-blocking iterator does not find any
     // kvs. Neither does it do any IOs to storage.
-    long numopen = TestGetTickerCount(options, NO_FILE_OPENS);
-    long cache_added = TestGetTickerCount(options, BLOCK_CACHE_ADD);
+    uint64_t numopen = TestGetTickerCount(options, NO_FILE_OPENS);
+    uint64_t cache_added = TestGetTickerCount(options, BLOCK_CACHE_ADD);
     iter = db_->NewIterator(non_blocking_opts, handles_[1]);
     count = 0;
     for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
@@ -5227,15 +5227,17 @@ class RecoveryTestHelper {
     test->Close();
 #endif
     if (trunc) {
-      ASSERT_EQ(0, truncate(fname.c_str(), size * off));
+      ASSERT_EQ(0, truncate(fname.c_str(),
+        static_cast<int64_t>(size * off)));
     } else {
-      InduceCorruption(fname, size * off, size * len);
+      InduceCorruption(fname, static_cast<size_t>(size * off),
+        static_cast<size_t>(size * len));
     }
   }
 
   // Overwrite data with 'a' from offset for length len
-  static void InduceCorruption(const std::string& filename, uint32_t offset,
-                               uint32_t len) {
+  static void InduceCorruption(const std::string& filename, size_t offset,
+                               size_t len) {
     ASSERT_GT(len, 0U);
 
     int fd = open(filename.c_str(), O_RDWR);
@@ -6439,7 +6441,7 @@ TEST_F(DBTest, RateLimitingTest) {
                   RandomString(&rnd, (1 << 10) + 1), wo));
   }
   uint64_t elapsed = env_->NowMicros() - start;
-  double raw_rate = env_->bytes_written_ * 1000000 / elapsed;
+  double raw_rate = env_->bytes_written_ * 1000000.0 / elapsed;
   Close();
 
   // # rate limiting with 0.7 x threshold
@@ -8126,7 +8128,7 @@ TEST_F(DBTest, MutexWaitStats) {
   options.create_if_missing = true;
   options.statistics = rocksdb::CreateDBStatistics();
   CreateAndReopenWithCF({"pikachu"}, options);
-  const int64_t kMutexWaitDelay = 100;
+  const uint64_t kMutexWaitDelay = 100;
   ThreadStatusUtil::TEST_SetStateDelay(
       ThreadStatus::STATE_MUTEX_WAIT, kMutexWaitDelay);
   ASSERT_OK(Put("hello", "rocksdb"));
diff --git a/db/event_helpers.cc b/db/event_helpers.cc
index 7191e4cc6..834ad9b1b 100644
--- a/db/event_helpers.cc
+++ b/db/event_helpers.cc
@@ -8,7 +8,10 @@
 namespace rocksdb {
 
 namespace {
-inline double SafeDivide(double a, double b) { return b == 0.0 ? 0 : a / b; }
+template<class T>
+inline T SafeDivide(T a, T b) {
+  return b == 0 ? 0 : a / b;
+}
 }  // namespace
 
 void EventHelpers::AppendCurrentTime(JSONWriter* jwriter) {
diff --git a/db/version_edit.h b/db/version_edit.h
index 412e7257c..65213ed1a 100644
--- a/db/version_edit.h
+++ b/db/version_edit.h
@@ -55,7 +55,8 @@ struct FileDescriptor {
     return packed_number_and_path_id & kFileNumberMask;
   }
   uint32_t GetPathId() const {
-    return packed_number_and_path_id / (kFileNumberMask + 1);
+    return static_cast<uint32_t>(
+        packed_number_and_path_id / (kFileNumberMask + 1));
   }
   uint64_t GetFileSize() const { return file_size; }
 };
diff --git a/db/version_set.cc b/db/version_set.cc
index 66762bebe..87d525581 100644
--- a/db/version_set.cc
+++ b/db/version_set.cc
@@ -738,24 +738,27 @@ uint64_t VersionStorageInfo::GetEstimatedActiveKeys() const {
   // (2) keys are directly overwritten
   // (3) deletion on non-existing keys
   // (4) low number of samples
-  if (current_num_samples_ == 0) {
+  if (num_samples_ == 0) {
     return 0;
   }
 
-  if (current_num_non_deletions_ <= current_num_deletions_) {
+  if (accumulated_num_non_deletions_ <= accumulated_num_deletions_) {
     return 0;
   }
 
-  uint64_t est = current_num_non_deletions_ - current_num_deletions_;
+  uint64_t est = accumulated_num_non_deletions_ - accumulated_num_deletions_;
 
   uint64_t file_count = 0;
   for (int level = 0; level < num_levels_; ++level) {
     file_count += files_[level].size();
   }
 
-  if (current_num_samples_ < file_count) {
+  if (num_samples_ < file_count) {
     // casting to avoid overflowing
-    return (est * static_cast<double>(file_count) / current_num_samples_);
+    return 
+      static_cast<uint64_t>(
+        (est * static_cast<double>(file_count) / current_num_samples_);
+      );
   } else {
     return est;
   }
diff --git a/memtable/hash_cuckoo_rep.cc b/memtable/hash_cuckoo_rep.cc
index fdf09c6f3..6f3cdbf67 100644
--- a/memtable/hash_cuckoo_rep.cc
+++ b/memtable/hash_cuckoo_rep.cc
@@ -624,8 +624,9 @@ MemTableRep* HashCuckooRepFactory::CreateMemTableRep(
   size_t pointer_size = sizeof(std::atomic<const char*>);
   assert(write_buffer_size_ >= (average_data_size_ + pointer_size));
   size_t bucket_count =
+    static_cast<size_t>(
       (write_buffer_size_ / (average_data_size_ + pointer_size)) / kFullness +
-      1;
+      1);
   unsigned int hash_function_count = hash_function_count_;
   if (hash_function_count < 2) {
     hash_function_count = 2;
@@ -635,7 +636,9 @@ MemTableRep* HashCuckooRepFactory::CreateMemTableRep(
   }
   return new HashCuckooRep(compare, allocator, bucket_count,
                            hash_function_count,
-                           (average_data_size_ + pointer_size) / kFullness);
+                           static_cast<size_t>(
+                             (average_data_size_ + pointer_size) / kFullness)
+                           );
 }
 
 MemTableRepFactory* NewHashCuckooRepFactory(size_t write_buffer_size,
diff --git a/port/win/env_win.cc b/port/win/env_win.cc
index 86f0e085e..81953a72c 100644
--- a/port/win/env_win.cc
+++ b/port/win/env_win.cc
@@ -1683,7 +1683,9 @@ class WinEnv : public Env {
 
   virtual Status GetHostName(char* name, uint64_t len) override {
     Status s;
-    DWORD nSize = len;
+    DWORD nSize = 
+      static_cast<DWORD>(std::min<uint64_t>(len,
+            std::numeric_limits<DWORD>::max()));
 
     if (!::GetComputerNameA(name, &nSize)) {
       auto lastError = GetLastError();
diff --git a/port/win/port_win.cc b/port/win/port_win.cc
index 99998b359..91c83b8c9 100644
--- a/port/win/port_win.cc
+++ b/port/win/port_win.cc
@@ -39,8 +39,9 @@ void gettimeofday(struct timeval* tv, struct timezone* /* tz */) {
 
   seconds secNow(duration_cast<seconds>(usNow));
 
-  tv->tv_sec = secNow.count();
-  tv->tv_usec = usNow.count() - duration_cast<microseconds>(secNow).count();
+  tv->tv_sec = static_cast<long>(secNow.count());
+  tv->tv_usec = static_cast<long>(usNow.count() - 
+      duration_cast<microseconds>(secNow).count());
 }
 
 Mutex::~Mutex() {}
diff --git a/table/cuckoo_table_builder.cc b/table/cuckoo_table_builder.cc
index 946a8b5fb..3a8f0365b 100644
--- a/table/cuckoo_table_builder.cc
+++ b/table/cuckoo_table_builder.cc
@@ -248,7 +248,8 @@ Status CuckooTableBuilder::Finish() {
   if (num_entries_ > 0) {
     // Calculate the real hash size if module hash is enabled.
     if (use_module_hash_) {
-      hash_table_size_ = num_entries_ / max_hash_table_ratio_;
+      hash_table_size_ = 
+        static_cast<uint64_t>(num_entries_ / max_hash_table_ratio_);
     }
     s = MakeHashTable(&buckets);
     if (!s.ok()) {
@@ -404,7 +405,8 @@ uint64_t CuckooTableBuilder::FileSize() const {
   }
 
   if (use_module_hash_) {
-    return (key_size_ + value_size_) * num_entries_ / max_hash_table_ratio_;
+    return static_cast<uint64_t>((key_size_ + value_size_) *
+        num_entries_ / max_hash_table_ratio_);
   } else {
     // Account for buckets being a power of two.
     // As elements are added, file size remains constant for a while and
diff --git a/table/cuckoo_table_builder_test.cc b/table/cuckoo_table_builder_test.cc
index 2ee87fb1e..a3cd21224 100644
--- a/table/cuckoo_table_builder_test.cc
+++ b/table/cuckoo_table_builder_test.cc
@@ -129,6 +129,11 @@ class CuckooBuilderTest : public testing::Test {
     return n;
   }
 
+  uint64_t GetExpectedTableSize(uint64_t num) {
+    return NextPowOf2(static_cast<uint64_t>(num / kHashTableRatio));
+  }
+
+
   Env* env_;
   EnvOptions env_options_;
   std::string fname;
@@ -169,7 +174,7 @@ TEST_F(CuckooBuilderTest, WriteSuccessNoCollisionFullKey) {
   for (auto& user_key : user_keys) {
     keys.push_back(GetInternalKey(user_key, false));
   }
-  uint64_t expected_table_size = NextPowOf2(keys.size() / kHashTableRatio);
+  uint64_t expected_table_size = GetExpectedTableSize(keys.size());
 
   unique_ptr<WritableFile> writable_file;
   fname = test::TmpDir() + "/NoCollisionFullKey";
@@ -216,7 +221,7 @@ TEST_F(CuckooBuilderTest, WriteSuccessWithCollisionFullKey) {
   for (auto& user_key : user_keys) {
     keys.push_back(GetInternalKey(user_key, false));
   }
-  uint64_t expected_table_size = NextPowOf2(keys.size() / kHashTableRatio);
+  uint64_t expected_table_size = GetExpectedTableSize(keys.size());
 
   unique_ptr<WritableFile> writable_file;
   fname = test::TmpDir() + "/WithCollisionFullKey";
@@ -263,7 +268,7 @@ TEST_F(CuckooBuilderTest, WriteSuccessWithCollisionAndCuckooBlock) {
   for (auto& user_key : user_keys) {
     keys.push_back(GetInternalKey(user_key, false));
   }
-  uint64_t expected_table_size = NextPowOf2(keys.size() / kHashTableRatio);
+  uint64_t expected_table_size = GetExpectedTableSize(keys.size());
 
   unique_ptr<WritableFile> writable_file;
   uint32_t cuckoo_block_size = 2;
@@ -316,7 +321,7 @@ TEST_F(CuckooBuilderTest, WithCollisionPathFullKey) {
   for (auto& user_key : user_keys) {
     keys.push_back(GetInternalKey(user_key, false));
   }
-  uint64_t expected_table_size = NextPowOf2(keys.size() / kHashTableRatio);
+  uint64_t expected_table_size = GetExpectedTableSize(keys.size());
 
   unique_ptr<WritableFile> writable_file;
   fname = test::TmpDir() + "/WithCollisionPathFullKey";
@@ -365,7 +370,7 @@ TEST_F(CuckooBuilderTest, WithCollisionPathFullKeyAndCuckooBlock) {
   for (auto& user_key : user_keys) {
     keys.push_back(GetInternalKey(user_key, false));
   }
-  uint64_t expected_table_size = NextPowOf2(keys.size() / kHashTableRatio);
+  uint64_t expected_table_size = GetExpectedTableSize(keys.size());
 
   unique_ptr<WritableFile> writable_file;
   fname = test::TmpDir() + "/WithCollisionPathFullKeyAndCuckooBlock";
@@ -407,7 +412,7 @@ TEST_F(CuckooBuilderTest, WriteSuccessNoCollisionUserKey) {
   hash_map = std::move(hm);
 
   std::vector<uint64_t> expected_locations = {0, 1, 2, 3};
-  uint64_t expected_table_size = NextPowOf2(user_keys.size() / kHashTableRatio);
+  uint64_t expected_table_size = GetExpectedTableSize(user_keys.size());
 
   unique_ptr<WritableFile> writable_file;
   fname = test::TmpDir() + "/NoCollisionUserKey";
@@ -450,7 +455,7 @@ TEST_F(CuckooBuilderTest, WriteSuccessWithCollisionUserKey) {
   hash_map = std::move(hm);
 
   std::vector<uint64_t> expected_locations = {0, 1, 2, 3};
-  uint64_t expected_table_size = NextPowOf2(user_keys.size() / kHashTableRatio);
+  uint64_t expected_table_size = GetExpectedTableSize(user_keys.size());
 
   unique_ptr<WritableFile> writable_file;
   fname = test::TmpDir() + "/WithCollisionUserKey";
@@ -495,7 +500,7 @@ TEST_F(CuckooBuilderTest, WithCollisionPathUserKey) {
   hash_map = std::move(hm);
 
   std::vector<uint64_t> expected_locations = {0, 1, 3, 4, 2};
-  uint64_t expected_table_size = NextPowOf2(user_keys.size() / kHashTableRatio);
+  uint64_t expected_table_size = GetExpectedTableSize(user_keys.size());
 
   unique_ptr<WritableFile> writable_file;
   fname = test::TmpDir() + "/WithCollisionPathUserKey";
diff --git a/table/cuckoo_table_reader_test.cc b/table/cuckoo_table_reader_test.cc
index 9758af3f2..c398b1383 100644
--- a/table/cuckoo_table_reader_test.cc
+++ b/table/cuckoo_table_reader_test.cc
@@ -500,7 +500,7 @@ void ReadKeys(uint64_t num, uint32_t batch_size) {
                  &get_context);
     }
   }
-  float time_per_op = (env->NowMicros() - start_time) * 1.0 / num;
+  float time_per_op = (env->NowMicros() - start_time) * 1.0f / num;
   fprintf(stderr,
       "Time taken per op is %.3fus (%.1f Mqps) with batch size of %u\n",
       time_per_op, 1.0 / time_per_op, batch_size);
diff --git a/table/plain_table_index.cc b/table/plain_table_index.cc
index 3e422c3c2..4f4ebabf1 100644
--- a/table/plain_table_index.cc
+++ b/table/plain_table_index.cc
@@ -117,7 +117,8 @@ void PlainTableIndexBuilder::AllocateIndex() {
     index_size_ = 1;
   } else {
     double hash_table_size_multipier = 1.0 / hash_table_ratio_;
-    index_size_ = num_prefixes_ * hash_table_size_multipier + 1;
+    index_size_ = 
+      static_cast<uint32_t>(num_prefixes_ * hash_table_size_multipier) + 1;
     assert(index_size_ > 0);
   }
 }
@@ -186,7 +187,7 @@ Slice PlainTableIndexBuilder::FillIndexes(
         index[i] = sub_index_offset | PlainTableIndex::kSubIndexMask;
         char* prev_ptr = &sub_index[sub_index_offset];
         char* cur_ptr = EncodeVarint32(prev_ptr, num_keys_for_bucket);
-        sub_index_offset += (cur_ptr - prev_ptr);
+        sub_index_offset += static_cast<uint32_t>(cur_ptr - prev_ptr);
         char* sub_index_pos = &sub_index[sub_index_offset];
         IndexRecord* record = hash_to_offsets[i];
         int j;
diff --git a/third-party/fbson/FbsonJsonParser.h b/third-party/fbson/FbsonJsonParser.h
index 3525b68b5..1c9c8ed6e 100644
--- a/third-party/fbson/FbsonJsonParser.h
+++ b/third-party/fbson/FbsonJsonParser.h
@@ -567,7 +567,7 @@ class FbsonJsonParserT {
         ++precision;
       } else if (ch == '.') {
         // note we don't pop out '.'
-        return parseDouble(in, val, precision, sign);
+        return parseDouble(in, static_cast<double>(val), precision, sign);
       } else {
         err_ = FbsonErrType::E_INVALID_DECIMAL;
         return false;
@@ -578,7 +578,7 @@ class FbsonJsonParserT {
       // if the number overflows int64_t, first parse it as double iff we see a
       // decimal point later. Otherwise, will treat it as overflow
       if (val < 0 && val > std::numeric_limits<int64_t>::min()) {
-        return parseDouble(in, (uint64_t)val, precision, sign);
+        return parseDouble(in, static_cast<double>(val), precision, sign);
       }
 
       ch = in.peek();
diff --git a/tools/db_stress.cc b/tools/db_stress.cc
index 669ca6c53..102803862 100644
--- a/tools/db_stress.cc
+++ b/tools/db_stress.cc
@@ -444,13 +444,13 @@ DEFINE_bool(use_merge, false, "On true, replaces all writes with a Merge "
 namespace rocksdb {
 
 // convert long to a big-endian slice key
-static std::string Key(long val) {
+static std::string Key(int64_t val) {
   std::string little_endian_key;
   std::string big_endian_key;
   PutFixed64(&little_endian_key, val);
   assert(little_endian_key.size() == sizeof(val));
   big_endian_key.resize(sizeof(val));
-  for (int i=0; i<(int)sizeof(val); i++) {
+  for (size_t i = 0 ; i < sizeof(val); ++i) {
     big_endian_key[i] = little_endian_key[sizeof(val) - 1 - i];
   }
   return big_endian_key;
@@ -472,9 +472,9 @@ namespace {
 
 class Stats {
  private:
-  double start_;
-  double finish_;
-  double seconds_;
+  uint64_t start_;
+  uint64_t finish_;
+  double  seconds_;
   long done_;
   long gets_;
   long prefixes_;
@@ -487,7 +487,7 @@ class Stats {
   long errors_;
   int next_report_;
   size_t bytes_;
-  double last_op_finish_;
+  uint64_t last_op_finish_;
   HistogramImpl hist_;
 
  public:
@@ -538,11 +538,11 @@ class Stats {
 
   void FinishedSingleOp() {
     if (FLAGS_histogram) {
-      double now = FLAGS_env->NowMicros();
-      double micros = now - last_op_finish_;
+      auto now = FLAGS_env->NowMicros();
+      auto micros = now - last_op_finish_;
       hist_.Add(micros);
       if (micros > 20000) {
-        fprintf(stdout, "long op: %.1f micros%30s\r", micros, "");
+        fprintf(stdout, "long op: %" PRIu64 " micros%30s\r", micros, "");
       }
       last_op_finish_ = now;
     }
@@ -676,7 +676,7 @@ class SharedState {
       values_[i] = std::vector<uint32_t>(max_key_, SENTINEL);
     }
 
-    long num_locks = (max_key_ >> log2_keys_per_lock_);
+    long num_locks = static_cast<long>(max_key_ >> log2_keys_per_lock_);
     if (max_key_ & ((1 << log2_keys_per_lock_) - 1)) {
       num_locks++;
     }
@@ -705,7 +705,7 @@ class SharedState {
     return stress_test_;
   }
 
-  long GetMaxKey() const {
+  int64_t GetMaxKey() const {
     return max_key_;
   }
 
@@ -785,21 +785,21 @@ class SharedState {
     std::fill(values_[cf].begin(), values_[cf].end(), SENTINEL);
   }
 
-  void Put(int cf, long key, uint32_t value_base) {
+  void Put(int cf, int64_t key, uint32_t value_base) {
     values_[cf][key] = value_base;
   }
 
-  uint32_t Get(int cf, long key) const { return values_[cf][key]; }
+  uint32_t Get(int cf, int64_t key) const { return values_[cf][key]; }
 
-  void Delete(int cf, long key) { values_[cf][key] = SENTINEL; }
+  void Delete(int cf, int64_t key) { values_[cf][key] = SENTINEL; }
 
-  void SingleDelete(int cf, size_t key) { values_[cf][key] = SENTINEL; }
+  void SingleDelete(int cf, int64_t key) { values_[cf][key] = SENTINEL; }
 
-  bool AllowsOverwrite(int cf, size_t key) {
+  bool AllowsOverwrite(int cf, int64_t key) {
     return no_overwrite_ids_[cf].find(key) == no_overwrite_ids_[cf].end();
   }
 
-  bool Exists(int cf, size_t key) { return values_[cf][key] != SENTINEL; }
+  bool Exists(int cf, int64_t key) { return values_[cf][key] != SENTINEL; }
 
   uint32_t GetSeed() const { return seed_; }
 
@@ -815,7 +815,7 @@ class SharedState {
   port::Mutex mu_;
   port::CondVar cv_;
   const uint32_t seed_;
-  const long max_key_;
+  const int64_t max_key_;
   const uint32_t log2_keys_per_lock_;
   const int num_threads_;
   long num_initialized_;
@@ -1122,9 +1122,9 @@ class StressTest {
         shared.GetCondVar()->Wait();
       }
 
-      double now = FLAGS_env->NowMicros();
+      auto now = FLAGS_env->NowMicros();
       fprintf(stdout, "%s Starting database operations\n",
-              FLAGS_env->TimeToString((uint64_t) now/1000000).c_str());
+              FLAGS_env->TimeToString(now/1000000).c_str());
 
       shared.SetStart();
       shared.GetCondVar()->SignalAll();
@@ -1157,10 +1157,10 @@ class StressTest {
       delete threads[i];
       threads[i] = nullptr;
     }
-    double now = FLAGS_env->NowMicros();
+    auto now = FLAGS_env->NowMicros();
     if (!FLAGS_test_batches_snapshots) {
       fprintf(stdout, "%s Verification successful\n",
-              FLAGS_env->TimeToString((uint64_t) now/1000000).c_str());
+              FLAGS_env->TimeToString(now/1000000).c_str());
     }
     PrintStatistics();
 
@@ -1510,7 +1510,7 @@ class StressTest {
     WriteOptions write_opts;
     auto shared = thread->shared;
     char value[100];
-    long max_key = thread->shared->GetMaxKey();
+    auto max_key = thread->shared->GetMaxKey();
     std::string from_db;
     if (FLAGS_sync) {
       write_opts.sync = true;
@@ -1760,7 +1760,7 @@ class StressTest {
         unique_ptr<Iterator> iter(
             db_->NewIterator(options, column_families_[cf]));
         iter->Seek(Key(start));
-        for (long i = start; i < end; i++) {
+        for (auto i = start; i < end; i++) {
           if (thread->shared->HasVerificationFailedYet()) {
             break;
           }
@@ -1798,7 +1798,7 @@ class StressTest {
         }
       } else {
         // Use Get to verify this range
-        for (long i = start; i < end; i++) {
+        for (auto i = start; i < end; i++) {
           if (thread->shared->HasVerificationFailedYet()) {
             break;
           }
@@ -1818,13 +1818,13 @@ class StressTest {
   }
 
   void VerificationAbort(SharedState* shared, std::string msg, int cf,
-                         long key) const {
-    printf("Verification failed for column family %d key %ld: %s\n", cf, key,
+                         int64_t key) const {
+    printf("Verification failed for column family %d key %" PRIi64 ": %s\n", cf, key,
            msg.c_str());
     shared->SetVerificationFailure();
   }
 
-  bool VerifyValue(int cf, long key, const ReadOptions& opts,
+  bool VerifyValue(int cf, int64_t key, const ReadOptions& opts,
                    SharedState* shared, const std::string& value_from_db,
                    Status s, bool strict = false) const {
     if (shared->HasVerificationFailedYet()) {
@@ -1861,12 +1861,12 @@ class StressTest {
     return true;
   }
 
-  static void PrintKeyValue(int cf, uint32_t key, const char* value,
+  static void PrintKeyValue(int cf, int64_t key, const char* value,
                             size_t sz) {
     if (!FLAGS_verbose) {
       return;
     }
-    fprintf(stdout, "[CF %d] %u ==> (%u) ", cf, key, (unsigned int)sz);
+    fprintf(stdout, "[CF %d] %" PRIi64 " == > (%" ROCKSDB_PRIszt ") ", cf, key, sz);
     for (size_t i = 0; i < sz; i++) {
       fprintf(stdout, "%X", value[i]);
     }
@@ -2127,9 +2127,9 @@ class StressTest {
     db_ = nullptr;
 
     num_times_reopened_++;
-    double now = FLAGS_env->NowMicros();
+    auto now = FLAGS_env->NowMicros();
     fprintf(stdout, "%s Reopening database for the %dth time\n",
-            FLAGS_env->TimeToString((uint64_t) now/1000000).c_str(),
+            FLAGS_env->TimeToString(now/1000000).c_str(),
             num_times_reopened_);
     Open();
   }
diff --git a/tools/ldb_cmd.h b/tools/ldb_cmd.h
index 71d5f647b..6a77b9710 100644
--- a/tools/ldb_cmd.h
+++ b/tools/ldb_cmd.h
@@ -150,7 +150,7 @@ public:
 
       if (i + 1 >= len) {
         // if odd number of chars than we just hit end of string
-        parsed.push_back(p - hexas);
+        parsed.push_back(static_cast<char>(p - hexas));
         break;
       }
 
@@ -158,7 +158,7 @@ public:
       const char* q = std::lower_bound(hexas, hexas + 16, b);
       if (*q == b) {
         // pairwise compute decimal value from hex
-        parsed.push_back(((p - hexas) << 4) | (q - hexas));
+        parsed.push_back(static_cast<char>(((p - hexas) << 4) | (q - hexas)));
       } else {
         throw "Invalid hex value";
       }
diff --git a/tools/write_stress.cc b/tools/write_stress.cc
index c0501faa5..05321fece 100644
--- a/tools/write_stress.cc
+++ b/tools/write_stress.cc
@@ -206,8 +206,9 @@ class WriteStress {
     std::uniform_real_distribution<double> dist(0, 1);
     std::uniform_int_distribution<int> char_dist('a', 'z');
     while (!stop_.load(std::memory_order_relaxed)) {
-      Env::Default()->SleepForMicroseconds(FLAGS_prefix_mutate_period_sec *
-                                           1000 * 1000LL);
+      Env::Default()->SleepForMicroseconds(static_cast<int>(
+                                           FLAGS_prefix_mutate_period_sec *
+                                           1000 * 1000LL));
       if (dist(rng) < FLAGS_first_char_mutate_probability) {
         key_prefix_[0].store(char_dist(rng), std::memory_order_relaxed);
       }
diff --git a/util/arena_test.cc b/util/arena_test.cc
index 8b74af90e..d4fa48cfc 100644
--- a/util/arena_test.cc
+++ b/util/arena_test.cc
@@ -25,7 +25,7 @@ bool CheckMemoryAllocated(size_t allocated, size_t expected) {
   // The value returned by Arena::MemoryAllocatedBytes() may be greater than
   // the requested memory. We choose a somewhat arbitrary upper bound of
   // max_expected = expected * 1.1 to detect critical overallocation.
-  size_t max_expected = expected * 1.1;
+  size_t max_expected = expected + expected / 10;
   return allocated >= expected && allocated <= max_expected;
 }
 
diff --git a/util/histogram.cc b/util/histogram.cc
index 4165121f0..dea3808c6 100644
--- a/util/histogram.cc
+++ b/util/histogram.cc
@@ -74,7 +74,7 @@ namespace {
 }
 
 void HistogramImpl::Clear() {
-  min_ = bucketMapper.LastValue();
+  min_ = static_cast<double>(bucketMapper.LastValue());
   max_ = 0;
   num_ = 0;
   sum_ = 0;
@@ -87,8 +87,8 @@ bool HistogramImpl::Empty() { return num_ == 0; }
 void HistogramImpl::Add(uint64_t value) {
   const size_t index = bucketMapper.IndexForValue(value);
   buckets_[index] += 1;
-  if (min_ > value) min_ = value;
-  if (max_ < value) max_ = value;
+  if (min_ > value) min_ = static_cast<double>(value);
+  if (max_ < value) max_ = static_cast<double>(value);
   num_++;
   sum_ += value;
   sum_squares_ += (value * value);
@@ -116,8 +116,10 @@ double HistogramImpl::Percentile(double p) const {
     sum += buckets_[b];
     if (sum >= threshold) {
       // Scale linearly within this bucket
-      double left_point = (b == 0) ? 0 : bucketMapper.BucketLimit(b-1);
-      double right_point = bucketMapper.BucketLimit(b);
+      double left_point = 
+        static_cast<double>((b == 0) ? 0 : bucketMapper.BucketLimit(b-1));
+      double right_point = 
+        static_cast<double>(bucketMapper.BucketLimit(b));
       double left_sum = sum - buckets_[b];
       double right_sum = sum;
       double pos = 0;
diff --git a/util/rate_limiter.h b/util/rate_limiter.h
index 2a54d4cba..91fc3c289 100644
--- a/util/rate_limiter.h
+++ b/util/rate_limiter.h
@@ -60,7 +60,7 @@ class GenericRateLimiter : public RateLimiter {
  private:
   void Refill();
   int64_t CalculateRefillBytesPerPeriod(int64_t rate_bytes_per_sec) {
-    return rate_bytes_per_sec * refill_period_us_ / 1000000.0;
+    return static_cast<int64_t>(rate_bytes_per_sec * refill_period_us_ / 1000000.0);
   }
 
   // This mutex guard all internal states
diff --git a/utilities/geodb/geodb_impl.cc b/utilities/geodb/geodb_impl.cc
index f509e277e..b30dd6333 100644
--- a/utilities/geodb/geodb_impl.cc
+++ b/utilities/geodb/geodb_impl.cc
@@ -352,8 +352,8 @@ Status GeoDBImpl::searchQuadIds(const GeoPosition& position,
   Pixel bottomRight =  PositionToPixel(bottomRightPos, Detail);
 
   // how many level of details to look for
-  int numberOfTilesAtMaxDepth = floor((bottomRight.x - topLeft.x) / 256);
-  int zoomLevelsToRise = floor(::log(numberOfTilesAtMaxDepth) / ::log(2));
+  int numberOfTilesAtMaxDepth = static_cast<int>(floor((bottomRight.x - topLeft.x) / 256));
+  int zoomLevelsToRise = static_cast<int>(floor(::log(numberOfTilesAtMaxDepth) / ::log(2)));
   zoomLevelsToRise++;
   int levels = std::max(0, Detail - zoomLevelsToRise);
 
@@ -408,8 +408,8 @@ GeoPosition GeoDBImpl::PixelToPosition(const Pixel& pixel, int levelOfDetail) {
 
 // Converts a Pixel to a Tile
 GeoDBImpl::Tile GeoDBImpl::PixelToTile(const Pixel& pixel) {
-  unsigned int tileX = floor(pixel.x / 256);
-  unsigned int tileY = floor(pixel.y / 256);
+  unsigned int tileX = static_cast<unsigned int>(floor(pixel.x / 256));
+  unsigned int tileY = static_cast<unsigned int>(floor(pixel.y / 256));
   return Tile(tileX, tileY);
 }
 
diff --git a/utilities/spatialdb/utils.h b/utilities/spatialdb/utils.h
index c65ccf561..b8c664a92 100644
--- a/utilities/spatialdb/utils.h
+++ b/utilities/spatialdb/utils.h
@@ -18,8 +18,8 @@ inline uint64_t GetTileFromCoord(double x, double start, double end,
   if (x < start) {
     return 0;
   }
-  uint64_t tiles = static_cast<uint64_t>(1) << tile_bits;
-  uint64_t r = ((x - start) / (end - start)) * tiles;
+  uint64_t tiles = 1ull << tile_bits;
+  uint64_t r = static_cast<uint64_t>(((x - start) / (end - start)) * tiles);
   return std::min(r, tiles - 1);
 }
 
@@ -27,7 +27,7 @@ inline uint64_t GetQuadKeyFromTile(uint64_t tile_x, uint64_t tile_y,
                                    uint32_t tile_bits) {
   uint64_t quad_key = 0;
   for (uint32_t i = 0; i < tile_bits; ++i) {
-    uint64_t mask = static_cast<uint64_t>(1LL << i);
+    uint64_t mask = (1ull << i);
     quad_key |= (tile_x & mask) << i;
     quad_key |= (tile_y & mask) << (i + 1);
   }