diff --git a/CMakeLists.txt b/CMakeLists.txt
index 28a320e5d..1610e0fbe 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -115,7 +115,7 @@ configure_file(util/build_version.cc.in ${BUILD_VERSION_CC} @ONLY)
 add_library(build_version OBJECT ${BUILD_VERSION_CC})
 target_include_directories(build_version PRIVATE
   ${CMAKE_CURRENT_SOURCE_DIR}/util)
-if(WIN32)
+if(MSVC)
   if (${USE_AVX2} EQUAL 1)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /Zi /nologo  /arch:AVX2 /EHsc /GS /Gd /GR /GF /fp:precise /Zc:wchar_t /Zc:forScope /errorReport:queue")
   else ()
@@ -126,6 +126,9 @@ if(WIN32)
 else()
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -W -Wextra -Wall")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wsign-compare -Wshadow -Wno-unused-parameter -Wno-unused-variable -Woverloaded-virtual -Wnon-virtual-dtor -Wno-missing-field-initializers")
+  if(MINGW)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-format")
+  endif()
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
   if(NOT CMAKE_BUILD_TYPE STREQUAL "Debug")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-omit-frame-pointer")
@@ -187,7 +190,7 @@ else()
    set(OPTIMIZE_DEBUG ${OPTIMIZE_DEBUG_DEFAULT})
 endif()
 
-if(WIN32)
+if(MSVC)
   if((${OPTIMIZE_DEBUG} EQUAL 1))
     message(STATUS "Debug optimization is enabled")
     set(CMAKE_CXX_FLAGS_DEBUG "/Oxt /MDd")
@@ -235,6 +238,9 @@ elseif(CMAKE_SYSTEM_NAME MATCHES "Android")
   add_definitions(-DOS_ANDROID)
 elseif(CMAKE_SYSTEM_NAME MATCHES "Windows")
   add_definitions(-DWIN32 -DOS_WIN -D_MBCS -DWIN64 -DNOMINMAX)
+  if(MINGW)
+    add_definitions(-D_WIN32_WINNT=_WIN32_WINNT_VISTA)
+  endif()
 endif()
 
 if(NOT WIN32)
@@ -514,18 +520,18 @@ add_library(${ROCKSDB_STATIC_LIB} STATIC ${SOURCES})
 target_link_libraries(${ROCKSDB_STATIC_LIB}
   ${THIRDPARTY_LIBS} ${SYSTEM_LIBS})
 
-if(WIN32)
-  set_target_properties(${ROCKSDB_STATIC_LIB} PROPERTIES
-    COMPILE_FLAGS "/Fd${CMAKE_CFG_INTDIR}/${ROCKSDB_STATIC_LIB}.pdb")
-endif()
-
 if(WIN32)
   add_library(${ROCKSDB_IMPORT_LIB} SHARED ${SOURCES})
   target_link_libraries(${ROCKSDB_IMPORT_LIB}
     ${THIRDPARTY_LIBS} ${SYSTEM_LIBS})
   set_target_properties(${ROCKSDB_IMPORT_LIB} PROPERTIES
-    COMPILE_FLAGS "-DROCKSDB_DLL -DROCKSDB_LIBRARY_EXPORTS /Fd${CMAKE_CFG_INTDIR}/${ROCKSDB_IMPORT_LIB}.pdb")
-else()
+    COMPILE_DEFINITIONS "ROCKSDB_DLL;ROCKSDB_LIBRARY_EXPORTS")
+  if(MSVC)
+    set_target_properties(${ROCKSDB_STATIC_LIB} PROPERTIES
+      COMPILE_FLAGS "/Fd${CMAKE_CFG_INTDIR}/${ROCKSDB_STATIC_LIB}.pdb")
+    set_target_properties(${ROCKSDB_IMPORT_LIB} PROPERTIES
+      COMPILE_FLAGS "/Fd${CMAKE_CFG_INTDIR}/${ROCKSDB_IMPORT_LIB}.pdb")
+  endif()
 endif()
 
 option(WITH_JNI "build with JNI" OFF)
@@ -692,7 +698,7 @@ enable_testing()
 add_custom_target(check COMMAND ${CMAKE_CTEST_COMMAND})
 set(TESTUTILLIB testutillib${ARTIFACT_SUFFIX})
 add_library(${TESTUTILLIB} STATIC ${TESTUTIL_SOURCE})
-if(WIN32)
+if(MSVC)
   set_target_properties(${TESTUTILLIB} PROPERTIES COMPILE_FLAGS "/Fd${CMAKE_CFG_INTDIR}/testutillib${ARTIFACT_SUFFIX}.pdb")
 endif()
 set_target_properties(${TESTUTILLIB}
diff --git a/db/write_batch_test.cc b/db/write_batch_test.cc
index 5a4bfb691..3006d19f2 100644
--- a/db/write_batch_test.cc
+++ b/db/write_batch_test.cc
@@ -478,7 +478,7 @@ TEST_F(WriteBatchTest, DISABLED_LargeKeyValue) {
   // Insert key and value of 3GB and push total batch size to 12GB.
   static const size_t kKeyValueSize = 3221225472u;
   std::string raw(kKeyValueSize, 'A');
-  WriteBatch batch(12884901888u + 1024u);
+  WriteBatch batch(size_t(12884901888ull + 1024u));
   for (char i = 0; i < 2; i++) {
     raw[0] = 'A' + i;
     raw[raw.length() - 1] = 'A' - i;
diff --git a/include/rocksdb/iostats_context.h b/include/rocksdb/iostats_context.h
index 632fe44c8..d9880136e 100644
--- a/include/rocksdb/iostats_context.h
+++ b/include/rocksdb/iostats_context.h
@@ -47,7 +47,7 @@ struct IOStatsContext {
 };
 
 #ifndef IOS_CROSS_COMPILE
-# ifdef _WIN32
+# ifdef _MSC_VER
 extern __declspec(thread) IOStatsContext iostats_context;
 # else
 extern __thread IOStatsContext iostats_context;
diff --git a/include/rocksdb/perf_context.h b/include/rocksdb/perf_context.h
index 2b2d6851a..7d20c846b 100644
--- a/include/rocksdb/perf_context.h
+++ b/include/rocksdb/perf_context.h
@@ -129,7 +129,7 @@ struct PerfContext {
 
 #if defined(NPERF_CONTEXT) || defined(IOS_CROSS_COMPILE)
 extern PerfContext perf_context;
-#elif _WIN32
+#elif defined(_MSC_VER)
 extern __declspec(thread) PerfContext perf_context;
 #else
 extern __thread PerfContext perf_context;
diff --git a/port/win/env_win.cc b/port/win/env_win.cc
index ced56f7fe..ee136cc62 100644
--- a/port/win/env_win.cc
+++ b/port/win/env_win.cc
@@ -647,7 +647,7 @@ uint64_t WinEnvIO::NowMicros() {
   if (GetSystemTimePreciseAsFileTime_ != NULL) {
     // all std::chrono clocks on windows proved to return
     // values that may repeat that is not good enough for some uses.
-    const int64_t c_UnixEpochStartTicks = 116444736000000000i64;
+    const int64_t c_UnixEpochStartTicks = 116444736000000000LL;
     const int64_t c_FtToMicroSec = 10;
 
     // This interface needs to return system time and not
diff --git a/port/win/port_win.cc b/port/win/port_win.cc
index dd87c3577..3a0535bd4 100644
--- a/port/win/port_win.cc
+++ b/port/win/port_win.cc
@@ -142,7 +142,7 @@ DIR* opendir(const char* name) {
     return nullptr;
   }
 
-  strncpy_s(dir->entry_.d_name, dir->data_.name, strlen(dir->data_.name));
+  strcpy_s(dir->entry_.d_name, sizeof(dir->entry_.d_name), dir->data_.name);
 
   return dir.release();
 }
@@ -164,7 +164,7 @@ struct dirent* readdir(DIR* dirp) {
     return nullptr;
   }
 
-  strncpy_s(dirp->entry_.d_name, dirp->data_.name, strlen(dirp->data_.name));
+  strcpy_s(dirp->entry_.d_name, sizeof(dirp->entry_.d_name), dirp->data_.name);
 
   return &dirp->entry_;
 }
diff --git a/port/win/port_win.h b/port/win/port_win.h
index a3860cde7..2b00819f6 100644
--- a/port/win/port_win.h
+++ b/port/win/port_win.h
@@ -47,7 +47,9 @@
 #undef GetCurrentTime
 #undef DeleteFile
 
+#ifndef _SSIZE_T_DEFINED
 typedef SSIZE_T ssize_t;
+#endif
 
 // size_t printf formatting named in the manner of C99 standard formatting
 // strings such as PRIu64
@@ -56,6 +58,7 @@ typedef SSIZE_T ssize_t;
 #define ROCKSDB_PRIszt "Iu"
 #endif
 
+#ifdef _MSC_VER
 #define __attribute__(A)
 
 // Thread local storage on Linux
@@ -64,6 +67,8 @@ typedef SSIZE_T ssize_t;
 #define __thread __declspec(thread)
 #endif
 
+#endif
+
 #ifndef PLATFORM_IS_LITTLE_ENDIAN
 #define PLATFORM_IS_LITTLE_ENDIAN (__BYTE_ORDER == __LITTLE_ENDIAN)
 #endif
diff --git a/port/win/win_logger.cc b/port/win/win_logger.cc
index 3c4ae1f88..3d1d94b63 100644
--- a/port/win/win_logger.cc
+++ b/port/win/win_logger.cc
@@ -31,12 +31,12 @@ namespace port {
 WinLogger::WinLogger(uint64_t (*gettid)(), Env* env, HANDLE file,
                      const InfoLogLevel log_level)
     : Logger(log_level),
+      file_(file),
       gettid_(gettid),
       log_size_(0),
       last_flush_micros_(0),
       env_(env),
-      flush_pending_(false),
-      file_(file) {}
+      flush_pending_(false) {}
 
 void WinLogger::DebugWriter(const char* str, int len) {
   DWORD bytesWritten = 0;
diff --git a/port/win/win_logger.h b/port/win/win_logger.h
index 84971363d..9e423d434 100644
--- a/port/win/win_logger.h
+++ b/port/win/win_logger.h
@@ -40,6 +40,7 @@ class WinLogger : public rocksdb::Logger {
 
   void Flush() override;
 
+  using rocksdb::Logger::Logv;
   void Logv(const char* format, va_list ap) override;
 
   size_t GetLogFileSize() const override;
diff --git a/third-party/gtest-1.7.0/fused-src/gtest/gtest-all.cc b/third-party/gtest-1.7.0/fused-src/gtest/gtest-all.cc
index 154ec6f26..e5c094583 100644
--- a/third-party/gtest-1.7.0/fused-src/gtest/gtest-all.cc
+++ b/third-party/gtest-1.7.0/fused-src/gtest/gtest-all.cc
@@ -8676,8 +8676,8 @@ void Notification::WaitForNotification() {
 }
 
 Mutex::Mutex()
-    : type_(kDynamic),
-      owner_thread_id_(0),
+    : owner_thread_id_(0),
+      type_(kDynamic),
       critical_section_init_phase_(0),
       critical_section_(new CRITICAL_SECTION) {
   ::InitializeCriticalSection(critical_section_);
diff --git a/util/arena.cc b/util/arena.cc
index 93d79d2b6..2fa225a77 100644
--- a/util/arena.cc
+++ b/util/arena.cc
@@ -26,7 +26,7 @@
 namespace rocksdb {
 
 // MSVC complains that it is already defined since it is static in the header.
-#ifndef OS_WIN
+#ifndef _MSC_VER
 const size_t Arena::kInlineSize;
 #endif
 
diff --git a/util/iostats_context.cc b/util/iostats_context.cc
index a3c72db96..ecb6a1582 100644
--- a/util/iostats_context.cc
+++ b/util/iostats_context.cc
@@ -10,7 +10,7 @@
 namespace rocksdb {
 
 #ifndef IOS_CROSS_COMPILE
-# ifdef _WIN32
+# ifdef _MSC_VER
 __declspec(thread) IOStatsContext iostats_context;
 # else
 __thread IOStatsContext iostats_context;
diff --git a/util/perf_context.cc b/util/perf_context.cc
index c18413d17..2eff8c192 100644
--- a/util/perf_context.cc
+++ b/util/perf_context.cc
@@ -11,7 +11,7 @@ namespace rocksdb {
 
 #if defined(NPERF_CONTEXT) || defined(IOS_CROSS_COMPILE)
   PerfContext perf_context;
-#elif _WIN32
+#elif defined(_MSC_VER)
   __declspec(thread) PerfContext perf_context;
 #else
   __thread PerfContext perf_context;
diff --git a/util/thread_local.cc b/util/thread_local.cc
index 4971dde8b..1b076b862 100644
--- a/util/thread_local.cc
+++ b/util/thread_local.cc
@@ -180,7 +180,7 @@ pthread_key_t thread_local_key = -1;
 void NTAPI WinOnThreadExit(PVOID module, DWORD reason, PVOID reserved) {
   // We decided to punt on PROCESS_EXIT
   if (DLL_THREAD_DETACH == reason) {
-    if (thread_local_key != -1 && thread_local_inclass_routine != nullptr) {
+    if (thread_local_key != pthread_key_t(-1) && thread_local_inclass_routine != nullptr) {
       void* tls = pthread_getspecific(thread_local_key);
       if (tls != nullptr) {
         thread_local_inclass_routine(tls);
@@ -191,22 +191,11 @@ void NTAPI WinOnThreadExit(PVOID module, DWORD reason, PVOID reserved) {
 
 }  // wintlscleanup
 
-#ifdef _WIN64
-
-#pragma comment(linker, "/include:_tls_used")
-#pragma comment(linker, "/include:p_thread_callback_on_exit")
-
-#else  // _WIN64
-
-#pragma comment(linker, "/INCLUDE:__tls_used")
-#pragma comment(linker, "/INCLUDE:_p_thread_callback_on_exit")
-
-#endif  // _WIN64
-
 // extern "C" suppresses C++ name mangling so we know the symbol name for the
 // linker /INCLUDE:symbol pragma above.
 extern "C" {
 
+#ifdef _MSC_VER
 // The linker must not discard thread_callback_on_exit.  (We force a reference
 // to this variable with a linker /include:symbol pragma to ensure that.) If
 // this variable is discarded, the OnThreadExit function will never be called.
@@ -222,6 +211,9 @@ const PIMAGE_TLS_CALLBACK p_thread_callback_on_exit =
 // Reset the default section.
 #pragma const_seg()
 
+#pragma comment(linker, "/include:_tls_used")
+#pragma comment(linker, "/include:p_thread_callback_on_exit")
+
 #else  // _WIN64
 
 #pragma data_seg(".CRT$XLB")
@@ -229,8 +221,19 @@ PIMAGE_TLS_CALLBACK p_thread_callback_on_exit = wintlscleanup::WinOnThreadExit;
 // Reset the default section.
 #pragma data_seg()
 
+#pragma comment(linker, "/INCLUDE:__tls_used")
+#pragma comment(linker, "/INCLUDE:_p_thread_callback_on_exit")
+
 #endif  // _WIN64
 
+#else
+// https://github.com/couchbase/gperftools/blob/master/src/windows/port.cc
+BOOL WINAPI DllMain(HINSTANCE h, DWORD dwReason, PVOID pv) {
+  if (dwReason == DLL_THREAD_DETACH)
+    wintlscleanup::WinOnThreadExit(h, dwReason, pv);
+  return TRUE;
+}
+#endif
 }  // extern "C"
 
 #endif  // OS_WIN
diff --git a/utilities/persistent_cache/persistent_cache_test.cc b/utilities/persistent_cache/persistent_cache_test.cc
index 12d24552e..56246c638 100644
--- a/utilities/persistent_cache/persistent_cache_test.cc
+++ b/utilities/persistent_cache/persistent_cache_test.cc
@@ -324,14 +324,14 @@ void PersistentCacheDBTest::RunTest(
     BlockBasedTableOptions table_options;
     table_options.cache_index_and_filter_blocks = true;
 
-    const uint64_t uint64_max = std::numeric_limits<uint64_t>::max();
+    const size_t size_max = std::numeric_limits<size_t>::max();
 
     switch (iter) {
       case 0:
         // page cache, block cache, no-compressed cache
         pcache = new_pcache(/*is_compressed=*/true);
         table_options.persistent_cache = pcache;
-        table_options.block_cache = NewLRUCache(uint64_max);
+        table_options.block_cache = NewLRUCache(size_max);
         table_options.block_cache_compressed = nullptr;
         options.table_factory.reset(NewBlockBasedTableFactory(table_options));
         break;
@@ -339,8 +339,8 @@ void PersistentCacheDBTest::RunTest(
         // page cache, block cache, compressed cache
         pcache = new_pcache(/*is_compressed=*/true);
         table_options.persistent_cache = pcache;
-        table_options.block_cache = NewLRUCache(uint64_max);
-        table_options.block_cache_compressed = NewLRUCache(uint64_max);
+        table_options.block_cache = NewLRUCache(size_max);
+        table_options.block_cache_compressed = NewLRUCache(size_max);
         options.table_factory.reset(NewBlockBasedTableFactory(table_options));
         break;
       case 2:
@@ -349,8 +349,8 @@ void PersistentCacheDBTest::RunTest(
         // also, make block cache sizes bigger, to trigger block cache hits
         pcache = new_pcache(/*is_compressed=*/true);
         table_options.persistent_cache = pcache;
-        table_options.block_cache = NewLRUCache(uint64_max);
-        table_options.block_cache_compressed = NewLRUCache(uint64_max);
+        table_options.block_cache = NewLRUCache(size_max);
+        table_options.block_cache_compressed = NewLRUCache(size_max);
         options.table_factory.reset(NewBlockBasedTableFactory(table_options));
         options.compression = kNoCompression;
         break;