Fix the deadlock issue in ThreadStatusSingleCompaction.

Summary:
Fix the deadlock issue in ThreadStatusSingleCompaction.

In the previous version of ThreadStatusSingleCompaction, the compaction
thread will wait for a SYNC_POINT while its db_mutex is held.  However,
if the test hasn't finished its Put cycle while a compaction is running,
a deadlock will happen in the test.

Test Plan:
export ROCKSDB_TESTS=ThreadStatus
./db_test

Reviewers: sdong, igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D35001

db/compaction_job.cc

@@ -229,12 +229,10 @@ CompactionJob::CompactionJob(
   ThreadStatusUtil::SetColumnFamily(
       compact_->compaction->column_family_data());
   ThreadStatusUtil::SetThreadOperation(ThreadStatus::OP_COMPACTION);
-  TEST_SYNC_POINT("CompactionJob::CompationJob()");
 }
 
 CompactionJob::~CompactionJob() {
   assert(compact_ == nullptr);
-  TEST_SYNC_POINT("CompactionJob::~CompactionJob()");
   ThreadStatusUtil::ResetThreadStatus();
 }
 
@@ -290,6 +288,7 @@ void CompactionJob::Prepare() {
 Status CompactionJob::Run() {
   AutoThreadOperationStageUpdater stage_updater(
       ThreadStatus::STAGE_COMPACTION_RUN);
+  TEST_SYNC_POINT("CompactionJob::Run():Start");
   log_buffer_->FlushBufferToLog();
   ColumnFamilyData* cfd = compact_->compaction->column_family_data();
 
@@ -481,6 +480,7 @@ Status CompactionJob::Run() {
   RecordCompactionIOStats();
 
   LogFlush(db_options_.info_log);
+  TEST_SYNC_POINT("CompactionJob::Run():End");
   return status;
 }
 

db/db_test.cc

@@ -10165,20 +10165,23 @@ TEST(DBTest, ThreadStatusSingleCompaction) {
   options.level0_file_num_compaction_trigger = kNumL0Files;
 
   rocksdb::SyncPoint::GetInstance()->LoadDependency({
-      {"CompactionJob::CompationJob()",
+      {"CompactionJob::Run():Start",
        "DBTest::ThreadStatusSingleCompaction:1"},
       {"DBTest::ThreadStatusSingleCompaction:2",
-       "CompactionJob::~CompactionJob()"},
+       "CompactionJob::Run():End"},
   });
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();
 
   for (int tests = 0; tests < 2; ++tests) {
-    TryReopen(options);
+    DestroyAndReopen(options);
 
     Random rnd(301);
     for (int key = kEntriesPerBuffer * kNumL0Files; key >= 0; --key) {
       ASSERT_OK(Put(ToString(key), RandomString(&rnd, kTestValueSize)));
     }
+    Flush();
+    ASSERT_GE(NumTableFilesAtLevel(0),
+              options.level0_file_num_compaction_trigger);
 
     // wait for compaction to be scheduled
     env_->SleepForMicroseconds(250000);