diff --git a/db/compaction_job.cc b/db/compaction_job.cc
index d836ccd30..7b786c116 100644
--- a/db/compaction_job.cc
+++ b/db/compaction_job.cc
@@ -50,6 +50,7 @@
 #include "util/iostats_context_imp.h"
 #include "util/stop_watch.h"
 #include "util/sync_point.h"
+#include "util/thread_status_util.h"
 
 namespace rocksdb {
 
@@ -270,6 +271,11 @@ void CompactionJob::Prepare() {
 Status CompactionJob::Run() {
   log_buffer_->FlushBufferToLog();
   ColumnFamilyData* cfd = compact_->compaction->column_family_data();
+  ThreadStatusUtil::SetColumnFamily(cfd);
+  ThreadStatusUtil::SetThreadOperation(ThreadStatus::OP_COMPACTION);
+#ifndef NDEBUG
+  ThreadStatusUtil::TEST_OperationDelay(ThreadStatus::OP_COMPACTION);
+#endif
 
   const uint64_t start_micros = env_->NowMicros();
   std::unique_ptr<Iterator> input(
@@ -459,6 +465,7 @@ Status CompactionJob::Run() {
   RecordCompactionIOStats();
 
   LogFlush(db_options_.info_log);
+  ThreadStatusUtil::ResetThreadStatus();
   return status;
 }
 
diff --git a/db/db_impl.cc b/db/db_impl.cc
index 4720742ae..f5d6d99f0 100644
--- a/db/db_impl.cc
+++ b/db/db_impl.cc
@@ -2145,6 +2145,14 @@ Status DBImpl::BackgroundCompaction(bool* madeProgress, JobContext* job_context,
     c->ReleaseCompactionFiles(status);
     *madeProgress = true;
   } else if (!is_manual && c->IsTrivialMove()) {
+    // Instrument for event update
+    // TODO(yhchiang): add op details for showing trivial-move.
+    ThreadStatusUtil::SetColumnFamily(c->column_family_data());
+    ThreadStatusUtil::SetThreadOperation(ThreadStatus::OP_COMPACTION);
+#ifndef NDEBUG
+    ThreadStatusUtil::TEST_OperationDelay(ThreadStatus::OP_COMPACTION);
+#endif
+
     // Move file to next level
     assert(c->num_input_files(0) == 1);
     FileMetaData* f = c->input(0, 0);
@@ -2171,6 +2179,9 @@ Status DBImpl::BackgroundCompaction(bool* madeProgress, JobContext* job_context,
         c->column_family_data()->current()->storage_info()->LevelSummary(&tmp));
     c->ReleaseCompactionFiles(status);
     *madeProgress = true;
+
+    // Clear Instrument
+    ThreadStatusUtil::ResetThreadStatus();
   } else {
     auto yield_callback = [&]() {
       return CallFlushDuringCompaction(c->column_family_data(),
diff --git a/db/db_impl.h b/db/db_impl.h
index de834a0fa..4664a3d60 100644
--- a/db/db_impl.h
+++ b/db/db_impl.h
@@ -234,6 +234,7 @@ class DBImpl : public DB {
   uint64_t TEST_max_total_in_memory_state() {
     return max_total_in_memory_state_;
   }
+
 #endif  // ROCKSDB_LITE
 
   // Returns the list of live files in 'live' and the list
diff --git a/db/db_impl_debug.cc b/db/db_impl_debug.cc
index 65eaff6b3..db4c91ae5 100644
--- a/db/db_impl_debug.cc
+++ b/db/db_impl_debug.cc
@@ -10,6 +10,7 @@
 #ifndef ROCKSDB_LITE
 
 #include "db/db_impl.h"
+#include "util/thread_status_updater.h"
 
 namespace rocksdb {
 
diff --git a/db/db_test.cc b/db/db_test.cc
index 9fa2a40b5..7146f9585 100644
--- a/db/db_test.cc
+++ b/db/db_test.cc
@@ -52,7 +52,7 @@
 #include "util/testutil.h"
 #include "util/mock_env.h"
 #include "util/string_util.h"
-#include "util/thread_status_updater.h"
+#include "util/thread_status_util.h"
 
 namespace rocksdb {
 
@@ -9414,7 +9414,7 @@ TEST(DBTest, DynamicMemtableOptions) {
 }
 
 #if ROCKSDB_USING_THREAD_STATUS
-TEST(DBTest, GetThreadList) {
+TEST(DBTest, GetThreadStatus) {
   Options options;
   options.env = env_;
   options.enable_thread_tracking = true;
@@ -9472,7 +9472,7 @@ TEST(DBTest, GetThreadList) {
       handles_, true);
 }
 
-TEST(DBTest, DisableThreadList) {
+TEST(DBTest, DisableThreadStatus) {
   Options options;
   options.env = env_;
   options.enable_thread_tracking = false;
@@ -9482,6 +9482,146 @@ TEST(DBTest, DisableThreadList) {
   env_->GetThreadStatusUpdater()->TEST_VerifyColumnFamilyInfoMap(
       handles_, false);
 }
+
+TEST(DBTest, ThreadStatusSingleCompaction) {
+  const int kTestKeySize = 16;
+  const int kTestValueSize = 984;
+  const int kEntrySize = kTestKeySize + kTestValueSize;
+  const int kEntriesPerBuffer = 100;
+  Options options;
+  options.create_if_missing = true;
+  options.write_buffer_size = kEntrySize * kEntriesPerBuffer;
+  options.compaction_style = kCompactionStyleLevel;
+  options.target_file_size_base = options.write_buffer_size;
+  options.max_bytes_for_level_base = options.target_file_size_base * 2;
+  options.max_bytes_for_level_multiplier = 2;
+  options.compression = kNoCompression;
+  options = CurrentOptions(options);
+  options.env = env_;
+  options.enable_thread_tracking = true;
+  const int kNumL0Files = 4;
+  options.level0_file_num_compaction_trigger = kNumL0Files;
+  for (int tests = 0; tests < 2; ++tests) {
+    TryReopen(options);
+    // Each compaction will run at least 2 seconds, which allows
+    // the test to capture the status of compaction with fewer
+    // false alarm.
+    const int kCompactionDelayMicro = 2000000;
+    ThreadStatusUtil::TEST_SetOperationDelay(
+        ThreadStatus::OP_COMPACTION, kCompactionDelayMicro);
+
+    Random rnd(301);
+    for (int key = kEntriesPerBuffer * kNumL0Files; key >= 0; --key) {
+      ASSERT_OK(Put(ToString(key), RandomString(&rnd, kTestValueSize)));
+    }
+
+    // wait for compaction to be scheduled
+    env_->SleepForMicroseconds(500000);
+
+    // check how many threads are doing compaction using GetThreadList
+    std::vector<ThreadStatus> thread_list;
+    Status s = env_->GetThreadList(&thread_list);
+    ASSERT_OK(s);
+    int compaction_count = 0;
+    for (auto thread : thread_list) {
+      if (thread.operation_type == ThreadStatus::OP_COMPACTION) {
+        compaction_count++;
+      }
+    }
+
+    if (options.enable_thread_tracking) {
+      // expecting one single L0 to L1 compaction
+      ASSERT_EQ(compaction_count, 1);
+    } else {
+      // If thread tracking is not enabled, compaction count should be 0.
+      ASSERT_EQ(compaction_count, 0);
+    }
+
+    ThreadStatusUtil::TEST_SetOperationDelay(
+        ThreadStatus::OP_COMPACTION, 0);
+
+    // repeat the test with disabling thread tracking.
+    options.enable_thread_tracking = false;
+  }
+}
+
+TEST(DBTest, ThreadStatusMultipleCompaction) {
+  const int kTestKeySize = 16;
+  const int kTestValueSize = 984;
+  const int kEntrySize = kTestKeySize + kTestValueSize;
+  const int kEntriesPerBuffer = 10;
+  const int kNumL0Files = 4;
+
+  const int kHighPriCount = 3;
+  const int kLowPriCount = 5;
+  env_->SetBackgroundThreads(kHighPriCount, Env::HIGH);
+  env_->SetBackgroundThreads(kLowPriCount, Env::LOW);
+
+  Options options;
+  options.create_if_missing = true;
+  options.write_buffer_size = kEntrySize * kEntriesPerBuffer;
+  options.compaction_style = kCompactionStyleLevel;
+  options.target_file_size_base = options.write_buffer_size;
+  options.max_bytes_for_level_base =
+      options.target_file_size_base * kNumL0Files;
+  options.compression = kNoCompression;
+  options = CurrentOptions(options);
+  options.env = env_;
+  options.enable_thread_tracking = true;
+  options.level0_file_num_compaction_trigger = kNumL0Files;
+  options.max_bytes_for_level_multiplier = 2;
+  options.max_background_compactions = kLowPriCount;
+
+  for (int tests = 0; tests < 2; ++tests) {
+    TryReopen(options);
+    Random rnd(301);
+
+    int max_compaction_count = 0;
+    std::vector<ThreadStatus> thread_list;
+    const int kCompactionDelayMicro = 10000;
+    ThreadStatusUtil::TEST_SetOperationDelay(
+        ThreadStatus::OP_COMPACTION, kCompactionDelayMicro);
+
+    // Make rocksdb busy
+    int key = 0;
+    for (int file = 0; file < 64 * kNumL0Files; ++file) {
+      for (int k = 0; k < kEntriesPerBuffer; ++k) {
+        ASSERT_OK(Put(ToString(key++), RandomString(&rnd, kTestValueSize)));
+      }
+
+      // check how many threads are doing compaction using GetThreadList
+      int compaction_count = 0;
+      Status s = env_->GetThreadList(&thread_list);
+      for (auto thread : thread_list) {
+        if (thread.operation_type == ThreadStatus::OP_COMPACTION) {
+          compaction_count++;
+        }
+      }
+
+      // Record the max number of compactions at a time.
+      if (max_compaction_count < compaction_count) {
+        max_compaction_count = compaction_count;
+      }
+    }
+
+    if (options.enable_thread_tracking) {
+      // Expect rocksdb max-out the concurrent compaction jobs.
+      ASSERT_EQ(max_compaction_count, options.max_background_compactions);
+    } else {
+      // If thread tracking is not enabled, compaction count should be 0.
+      ASSERT_EQ(max_compaction_count, 0);
+    }
+
+    // repeat the test with disabling thread tracking.
+    options.enable_thread_tracking = false;
+  }
+
+  ThreadStatusUtil::TEST_SetOperationDelay(
+      ThreadStatus::OP_COMPACTION, 0);
+}
+
+
+
 #endif  // ROCKSDB_USING_THREAD_STATUS
 
 TEST(DBTest, DynamicCompactionOptions) {
diff --git a/util/thread_event_info.h b/util/thread_event_info.h
new file mode 100644
index 000000000..28916deb4
--- /dev/null
+++ b/util/thread_event_info.h
@@ -0,0 +1,71 @@
+// Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+// This source code is licensed under the BSD-style license found in the
+// LICENSE file in the root directory of this source tree. An additional grant
+// of patent rights can be found in the PATENTS file in the same directory.
+//
+// This file defines the structures for thread event and operation.
+// Thread events are used to describe high level action of a
+// thread such as doing compaction or flush, while thread operation
+// are used to describe lower-level action such as reading /
+// writing a file or waiting for a mutex.  Events and operations
+// are designed to be independent.  Typically, a thread usually involves
+// in one event and one operation at any specific point in time.
+
+#pragma once
+
+#include "include/rocksdb/thread_status.h"
+
+#include <string>
+
+namespace rocksdb {
+
+#if ROCKSDB_USING_THREAD_STATUS
+
+// The structure that describes a major thread event.
+struct EventInfo {
+  const ThreadStatus::EventType code;
+  const std::string name;
+};
+
+// The global event table.
+//
+// When updating a status of a thread, the pointer of the EventInfo
+// of the current ThreadStatusData will be pointing to one of the
+// rows in this global table.
+//
+// Note that it's not designed to be constant as in the future we
+// might consider adding global count to the EventInfo.
+static EventInfo global_event_table[] = {
+  {ThreadStatus::EVENT_UNKNOWN, ""},
+  {ThreadStatus::EVENT_COMPACTION, "Compaction"},
+  {ThreadStatus::EVENT_FLUSH, "Flush"}
+};
+
+// The structure that describes a operation.
+struct OperationInfo {
+  const ThreadStatus::OperationType code;
+  const std::string name;
+};
+
+// The global operation table.
+//
+// When updating a status of a thread, the pointer of the OperationInfo
+// of the current ThreadStatusData will be pointing to one of the
+// rows in this global table.
+static OperationInfo global_operation_table[] = {
+  {ThreadStatus::OPERATION_UNKNOWN, ""},
+  {ThreadStatus::OPERATION_WRITE_FILE, "Writing SST file"},
+  {ThreadStatus::OPERATION_READ_FILE, "Reaing SST file"},
+  {ThreadStatus::OPERATION_WAIT_DB_MUTEX, "Waiting DB Mutex"}
+};
+
+#else
+
+struct EventInfo {
+};
+
+struct OperationInfo {
+};
+
+#endif  // ROCKSDB_USING_THREAD_STATUS
+}  // namespace rocksdb
diff --git a/util/thread_status_updater.cc b/util/thread_status_updater.cc
index feb129885..25f7b1c5c 100644
--- a/util/thread_status_updater.cc
+++ b/util/thread_status_updater.cc
@@ -29,20 +29,46 @@ void ThreadStatusUpdater::SetThreadType(
   data->thread_type.store(ttype, std::memory_order_relaxed);
 }
 
+void ThreadStatusUpdater::ResetThreadStatus() {
+  ClearThreadState();
+  ClearThreadOperation();
+  SetColumnFamilyInfoKey(nullptr);
+}
+
 void ThreadStatusUpdater::SetColumnFamilyInfoKey(
     const void* cf_key) {
   auto* data = InitAndGet();
+  // set the tracking flag based on whether cf_key is non-null or not.
+  // If enable_thread_tracking is set to false, the input cf_key
+  // would be nullptr.
+  data->enable_tracking = (cf_key != nullptr);
   data->cf_key.store(cf_key, std::memory_order_relaxed);
 }
 
+const void* ThreadStatusUpdater::GetColumnFamilyInfoKey() {
+  auto* data = InitAndGet();
+  if (data->enable_tracking == false) {
+    return nullptr;
+  }
+  return data->cf_key.load(std::memory_order_relaxed);
+}
+
 void ThreadStatusUpdater::SetThreadOperation(
     const ThreadStatus::OperationType type) {
   auto* data = InitAndGet();
+  if (!data->enable_tracking) {
+    assert(data->cf_key.load(std::memory_order_relaxed) == nullptr);
+    return;
+  }
   data->operation_type.store(type, std::memory_order_relaxed);
 }
 
 void ThreadStatusUpdater::ClearThreadOperation() {
   auto* data = InitAndGet();
+  if (!data->enable_tracking) {
+    assert(data->cf_key.load(std::memory_order_relaxed) == nullptr);
+    return;
+  }
   data->operation_type.store(
       ThreadStatus::OP_UNKNOWN, std::memory_order_relaxed);
 }
@@ -50,11 +76,19 @@ void ThreadStatusUpdater::ClearThreadOperation() {
 void ThreadStatusUpdater::SetThreadState(
     const ThreadStatus::StateType type) {
   auto* data = InitAndGet();
+  if (!data->enable_tracking) {
+    assert(data->cf_key.load(std::memory_order_relaxed) == nullptr);
+    return;
+  }
   data->state_type.store(type, std::memory_order_relaxed);
 }
 
 void ThreadStatusUpdater::ClearThreadState() {
   auto* data = InitAndGet();
+  if (!data->enable_tracking) {
+    assert(data->cf_key.load(std::memory_order_relaxed) == nullptr);
+    return;
+  }
   data->state_type.store(
       ThreadStatus::STATE_UNKNOWN, std::memory_order_relaxed);
 }
@@ -176,6 +210,9 @@ void ThreadStatusUpdater::EraseDatabaseInfo(const void* db_key) {
 void ThreadStatusUpdater::UnregisterThread() {
 }
 
+void ThreadStatusUpdater::ResetThreadStatus() {
+}
+
 void ThreadStatusUpdater::SetThreadType(
     ThreadStatus::ThreadType ttype) {
 }
diff --git a/util/thread_status_updater.h b/util/thread_status_updater.h
index c97102a96..5d4e55bb2 100644
--- a/util/thread_status_updater.h
+++ b/util/thread_status_updater.h
@@ -64,13 +64,24 @@ struct ConstantColumnFamilyInfo {
 // status of a thread using a set of atomic pointers.
 struct ThreadStatusData {
 #if ROCKSDB_USING_THREAD_STATUS
-  explicit ThreadStatusData() : thread_id(0) {
+  explicit ThreadStatusData() : thread_id(0), enable_tracking(false) {
     thread_type.store(ThreadStatus::USER);
-    cf_key.store(0);
+    cf_key.store(nullptr);
     operation_type.store(ThreadStatus::OP_UNKNOWN);
     state_type.store(ThreadStatus::STATE_UNKNOWN);
   }
+
   uint64_t thread_id;
+
+  // A flag to indicate whether the thread tracking is enabled
+  // in the current thread.  This value will be updated based on whether
+  // the associated Options::enable_thread_tracking is set to true
+  // in ThreadStatusUtil::SetColumnFamily().
+  //
+  // If set to false, then SetThreadOperation and SetThreadState
+  // will be no-op.
+  bool enable_tracking;
+
   std::atomic<ThreadStatus::ThreadType> thread_type;
   std::atomic<const void*> cf_key;
   std::atomic<ThreadStatus::OperationType> operation_type;
@@ -96,6 +107,10 @@ class ThreadStatusUpdater {
   // Unregister the current thread.
   void UnregisterThread();
 
+  // Reset the status of the current thread.  This includes resetting
+  // ColumnFamilyInfoKey, ThreadOperation, and ThreadState.
+  void ResetThreadStatus();
+
   // Set the thread type of the current thread.
   void SetThreadType(ThreadStatus::ThreadType ttype);
 
@@ -103,6 +118,9 @@ class ThreadStatusUpdater {
   // its thread-local pointer of ThreadStateInfo to the correct entry.
   void SetColumnFamilyInfoKey(const void* cf_key);
 
+  // returns the column family info key.
+  const void* GetColumnFamilyInfoKey();
+
   // Update the thread operation of the current thread.
   void SetThreadOperation(const ThreadStatus::OperationType type);
 
@@ -143,7 +161,6 @@ class ThreadStatusUpdater {
       bool check_exist);
 
  protected:
-
 #if ROCKSDB_USING_THREAD_STATUS
   // The thread-local variable for storing thread status.
   static __thread ThreadStatusData* thread_status_data_;
@@ -169,6 +186,7 @@ class ThreadStatusUpdater {
   // associated to the same db_key faster.
   std::unordered_map<
       const void*, std::unordered_set<const void*>> db_key_map_;
+
 #else
   static ThreadStatusData* thread_status_data_;
 #endif  // ROCKSDB_USING_THREAD_STATUS
diff --git a/util/thread_status_updater_debug.cc b/util/thread_status_updater_debug.cc
index 1f53e5fc1..274f427d3 100644
--- a/util/thread_status_updater_debug.cc
+++ b/util/thread_status_updater_debug.cc
@@ -7,9 +7,11 @@
 
 #include "util/thread_status_updater.h"
 #include "db/column_family.h"
-#if ROCKSDB_USING_THREAD_STATUS
 
 namespace rocksdb {
+
+#ifndef NDEBUG
+#if ROCKSDB_USING_THREAD_STATUS
 void ThreadStatusUpdater::TEST_VerifyColumnFamilyInfoMap(
     const std::vector<ColumnFamilyHandle*>& handles,
     bool check_exist) {
@@ -29,5 +31,16 @@ void ThreadStatusUpdater::TEST_VerifyColumnFamilyInfoMap(
     }
   }
 }
-}  // namespace rocksdb
+
+#else
+
+void ThreadStatusUpdater::TEST_VerifyColumnFamilyInfoMap(
+    const std::vector<ColumnFamilyHandle*>& handles,
+    bool check_exist) {
+}
+
 #endif  // ROCKSDB_USING_THREAD_STATUS
+#endif  // !NDEBUG
+
+
+}  // namespace rocksdb
diff --git a/util/thread_status_util.cc b/util/thread_status_util.cc
index c8767d9a8..970f79ae8 100644
--- a/util/thread_status_util.cc
+++ b/util/thread_status_util.cc
@@ -9,6 +9,7 @@
 
 namespace rocksdb {
 
+
 #if ROCKSDB_USING_THREAD_STATUS
 __thread ThreadStatusUpdater*
     ThreadStatusUtil::thread_updater_local_cache_ = nullptr;
@@ -36,7 +37,41 @@ void ThreadStatusUtil::SetColumnFamily(const ColumnFamilyData* cfd) {
     return;
   }
   assert(thread_updater_local_cache_);
-  thread_updater_local_cache_->SetColumnFamilyInfoKey(cfd);
+  if (cfd != nullptr && cfd->options()->enable_thread_tracking) {
+    thread_updater_local_cache_->SetColumnFamilyInfoKey(cfd);
+  } else {
+    // When cfd == nullptr or enable_thread_tracking == false, we set
+    // ColumnFamilyInfoKey to nullptr, which makes SetThreadOperation
+    // and SetThreadState become no-op.
+    thread_updater_local_cache_->SetColumnFamilyInfoKey(nullptr);
+  }
+}
+
+void ThreadStatusUtil::SetThreadOperation(ThreadStatus::OperationType op) {
+  if (thread_updater_local_cache_ == nullptr) {
+    // thread_updater_local_cache_ must be set in SetColumnFamily
+    // or other ThreadStatusUtil functions.
+    return;
+  }
+
+  thread_updater_local_cache_->SetThreadOperation(op);
+}
+
+void ThreadStatusUtil::SetThreadState(ThreadStatus::StateType state) {
+  if (thread_updater_local_cache_ == nullptr) {
+    // thread_updater_local_cache_ must be set in SetColumnFamily
+    // or other ThreadStatusUtil functions.
+    return;
+  }
+
+  thread_updater_local_cache_->SetThreadState(state);
+}
+
+void ThreadStatusUtil::ResetThreadStatus() {
+  if (thread_updater_local_cache_ == nullptr) {
+    return;
+  }
+  thread_updater_local_cache_->ResetThreadStatus();
 }
 
 void ThreadStatusUtil::NewColumnFamilyInfo(
@@ -86,6 +121,12 @@ bool ThreadStatusUtil::MaybeInitThreadLocalUpdater(const Env* env) {
 void ThreadStatusUtil::SetColumnFamily(const ColumnFamilyData* cfd) {
 }
 
+void ThreadStatusUtil::SetThreadOperation(ThreadStatus::OperationType op) {
+}
+
+void ThreadStatusUtil::SetThreadState(ThreadStatus::StateType state) {
+}
+
 void ThreadStatusUtil::NewColumnFamilyInfo(
     const DB* db, const ColumnFamilyData* cfd) {
 }
@@ -97,6 +138,9 @@ void ThreadStatusUtil::EraseColumnFamilyInfo(
 void ThreadStatusUtil::EraseDatabaseInfo(const DB* db) {
 }
 
+void ThreadStatusUtil::ResetThreadStatus() {
+}
+
 #endif  // ROCKSDB_USING_THREAD_STATUS
 
 }  // namespace rocksdb
diff --git a/util/thread_status_util.h b/util/thread_status_util.h
index c583d5a5d..a8549e8ae 100644
--- a/util/thread_status_util.h
+++ b/util/thread_status_util.h
@@ -12,6 +12,7 @@
 
 namespace rocksdb {
 
+
 // The static utility class for updating thread-local status.
 //
 // The thread-local status is updated via the thread-local cached
@@ -52,6 +53,22 @@ class ThreadStatusUtil {
   // something related to the specified column family.
   static void SetColumnFamily(const ColumnFamilyData* cfd);
 
+  static void SetThreadOperation(ThreadStatus::OperationType type);
+
+  static void SetThreadState(ThreadStatus::StateType type);
+
+  static void ResetThreadStatus();
+
+#ifndef NDEBUG
+  static void TEST_SetOperationDelay(
+      const ThreadStatus::OperationType operation, int micro);
+  static void TEST_OperationDelay(
+      const ThreadStatus::OperationType operation);
+  static void TEST_SetStateDelay(
+      const ThreadStatus::StateType state, int micro);
+  static void TEST_StateDelay(const ThreadStatus::StateType state);
+#endif
+
  protected:
   // Initialize the thread-local ThreadStatusUpdater when it finds
   // the cached value is nullptr.  Returns true if it has cached
diff --git a/util/thread_status_util_debug.cc b/util/thread_status_util_debug.cc
new file mode 100644
index 000000000..5378acaf8
--- /dev/null
+++ b/util/thread_status_util_debug.cc
@@ -0,0 +1,41 @@
+// Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+// This source code is licensed under the BSD-style license found in the
+// LICENSE file in the root directory of this source tree. An additional grant
+// of patent rights can be found in the PATENTS file in the same directory.
+
+#include "rocksdb/env.h"
+#include "util/thread_status_updater.h"
+#include "util/thread_status_util.h"
+
+namespace rocksdb {
+
+#ifndef NDEBUG
+// the delay for debugging purpose.
+static int operations_delay[ThreadStatus::NUM_OP_TYPES] ={0};
+static int states_delay[ThreadStatus::NUM_STATE_TYPES] = {0};
+
+void ThreadStatusUtil::TEST_SetStateDelay(
+    const ThreadStatus::StateType state, int micro) {
+  states_delay[state] = micro;
+}
+
+void ThreadStatusUtil::TEST_StateDelay(
+    const ThreadStatus::StateType state) {
+  Env::Default()->SleepForMicroseconds(
+      states_delay[state]);
+}
+
+void ThreadStatusUtil::TEST_SetOperationDelay(
+    const ThreadStatus::OperationType operation, int micro) {
+  operations_delay[operation] = micro;
+}
+
+
+void ThreadStatusUtil::TEST_OperationDelay(
+    const ThreadStatus::OperationType operation) {
+  Env::Default()->SleepForMicroseconds(
+      operations_delay[operation]);
+}
+#endif  // !NDEBUG
+
+}  // namespace rocksdb