Fixed a bug which causes rocksdb.flush.write.bytes stat is always zero

Summary: Fixed a bug which causes rocksdb.flush.write.bytes stat is always zero

Test Plan: augment existing db_test

Reviewers: sdong, anthony, IslamAbdelRahman, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D47595

db/builder.cc

@@ -103,9 +103,8 @@ Status BuildTable(
       // TODO(noetzli): Update stats after flush, too.
       if (io_priority == Env::IO_HIGH &&
           IOSTATS(bytes_written) >= kReportFlushIOStatsEvery) {
-        ThreadStatusUtil::IncreaseThreadOperationProperty(
+        ThreadStatusUtil::SetThreadOperationProperty(
             ThreadStatus::FLUSH_BYTES_WRITTEN, IOSTATS(bytes_written));
-        IOSTATS_RESET(bytes_written);
       }
     }
 

db/db_test.cc

@@ -8121,6 +8121,9 @@ TEST_F(DBTest, MergeTestTime) {
 
   ASSERT_LT(TestGetTickerCount(options, MERGE_OPERATION_TOTAL_TIME), 6000000);
   ASSERT_GT(TestGetTickerCount(options, MERGE_OPERATION_TOTAL_TIME), 3200000);
+#if ROCKSDB_USING_THREAD_STATUS
+  ASSERT_GT(TestGetTickerCount(options, FLUSH_WRITE_BYTES), 0);
+#endif  // ROCKSDB_USING_THREAD_STATUS
 }
 
 TEST_P(DBTestWithParam, MergeCompactionTimeTest) {

db/flush_job.cc

@@ -111,9 +111,8 @@ void FlushJob::ReportFlushInputSize(const autovector<MemTable*>& mems) {
 }
 
 void FlushJob::RecordFlushIOStats() {
-  ThreadStatusUtil::IncreaseThreadOperationProperty(
+  ThreadStatusUtil::SetThreadOperationProperty(
       ThreadStatus::FLUSH_BYTES_WRITTEN, IOSTATS(bytes_written));
-  IOSTATS_RESET(bytes_written);
 }
 
 Status FlushJob::Run(FileMetaData* file_meta) {