Add enable_thread_tracking to DBOptions

Summary:
Add enable_thread_tracking to DBOptions to allow
tracking thread status related to the DB.  Default is off.

Test Plan:
export ROCKSDB_TESTS=ThreadList
./db_test

Reviewers: ljin, sdong, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D29289

db/db_impl.cc

@@ -3725,17 +3725,23 @@ Status DestroyDB(const std::string& dbname, const Options& options) {
 #if ROCKSDB_USING_THREAD_STATUS
 void DBImpl::NewThreadStatusCfInfo(
     ColumnFamilyData* cfd) const {
-  ThreadStatusImpl::NewColumnFamilyInfo(
-      this, GetName(), cfd, cfd->GetName());
+  if (db_options_.enable_thread_tracking) {
+    ThreadStatusImpl::NewColumnFamilyInfo(
+        this, GetName(), cfd, cfd->GetName());
+  }
 }
 
 void DBImpl::EraseThreadStatusCfInfo(
     ColumnFamilyData* cfd) const {
-  ThreadStatusImpl::EraseColumnFamilyInfo(cfd);
+  if (db_options_.enable_thread_tracking) {
+    ThreadStatusImpl::EraseColumnFamilyInfo(cfd);
+  }
 }
 
 void DBImpl::EraseThreadStatusDbInfo() const {
-  ThreadStatusImpl::EraseDatabaseInfo(this);
+  if (db_options_.enable_thread_tracking) {
+    ThreadStatusImpl::EraseDatabaseInfo(this);
+  }
 }
 
 Status GetThreadList(std::vector<ThreadStatus>* thread_list) {

db/db_test.cc

@@ -8986,6 +8986,8 @@ TEST(DBTest, DynamicMemtableOptions) {
 TEST(DBTest, GetThreadList) {
   Options options;
   options.env = env_;
+  options.enable_thread_tracking = true;
+  TryReopen(options);
 
   std::vector<ThreadStatus> thread_list;
   Status s = GetThreadList(&thread_list);
@@ -9025,14 +9027,24 @@ TEST(DBTest, GetThreadList) {
     if (i == 0) {
       // repeat the test with multiple column families
       CreateAndReopenWithCF({"pikachu", "about-to-remove"}, options);
-      ThreadStatusImpl::TEST_VerifyColumnFamilyInfoMap(handles_);
+      ThreadStatusImpl::TEST_VerifyColumnFamilyInfoMap(handles_, true);
     }
   }
   db_->DropColumnFamily(handles_[2]);
   handles_.erase(handles_.begin() + 2);
-  ThreadStatusImpl::TEST_VerifyColumnFamilyInfoMap(handles_);
+  ThreadStatusImpl::TEST_VerifyColumnFamilyInfoMap(handles_, true);
   Close();
-  ThreadStatusImpl::TEST_VerifyColumnFamilyInfoMap(handles_);
+  ThreadStatusImpl::TEST_VerifyColumnFamilyInfoMap(handles_, true);
+}
+
+TEST(DBTest, DisableThreadList) {
+  Options options;
+  options.env = env_;
+  options.enable_thread_tracking = false;
+  TryReopen(options);
+  CreateAndReopenWithCF({"pikachu", "about-to-remove"}, options);
+  // Verify non of the column family info exists
+  ThreadStatusImpl::TEST_VerifyColumnFamilyInfoMap(handles_, false);
 }
 #endif  // ROCKSDB_USING_THREAD_STATUS
 

include/rocksdb/options.h

@@ -884,6 +884,12 @@ struct DBOptions {
   // When rate limiter is enabled, it automatically enables bytes_per_sync
   // to 1MB.
   uint64_t bytes_per_sync;
+
+  // If true, then the status of the threads involved in this DB will
+  // be tracked and available via GetThreadList() API.
+  //
+  // Default: false
+  bool enable_thread_tracking;
 };
 
 // Options to control the behavior of a database (passed to DB::Open)

util/options.cc

@@ -232,7 +232,8 @@ DBOptions::DBOptions()
       advise_random_on_open(true),
       access_hint_on_compaction_start(NORMAL),
       use_adaptive_mutex(false),
-      bytes_per_sync(0) {}
+      bytes_per_sync(0),
+      enable_thread_tracking(false) {}
 
 DBOptions::DBOptions(const Options& options)
     : create_if_missing(options.create_if_missing),
@@ -274,7 +275,8 @@ DBOptions::DBOptions(const Options& options)
       advise_random_on_open(options.advise_random_on_open),
       access_hint_on_compaction_start(options.access_hint_on_compaction_start),
       use_adaptive_mutex(options.use_adaptive_mutex),
-      bytes_per_sync(options.bytes_per_sync) {}
+      bytes_per_sync(options.bytes_per_sync),
+      enable_thread_tracking(options.enable_thread_tracking) {}
 
 static const char* const access_hints[] = {
   "NONE", "NORMAL", "SEQUENTIAL", "WILLNEED"
@@ -342,6 +344,8 @@ void DBOptions::Dump(Logger* log) const {
         rate_limiter.get());
     Log(log, "                          Options.bytes_per_sync: %" PRIu64,
         bytes_per_sync);
+    Log(log, "                    enable_thread_tracking: %d",
+        enable_thread_tracking);
 }  // DBOptions::Dump
 
 void ColumnFamilyOptions::Dump(Logger* log) const {

util/thread_status_impl.h

@@ -127,7 +127,8 @@ class ThreadStatusImpl {
   // Verifies whether the input ColumnFamilyHandles matches
   // the information stored in the current cf_info_map.
   static void TEST_VerifyColumnFamilyInfoMap(
-      const std::vector<ColumnFamilyHandle*>& handles);
+      const std::vector<ColumnFamilyHandle*>& handles,
+      bool check_exist);
 
  protected:
   // The thread-local variable for storing thread status.

util/thread_status_impl_debug.cc

@@ -11,15 +11,22 @@
 
 namespace rocksdb {
 void ThreadStatusImpl::TEST_VerifyColumnFamilyInfoMap(
-    const std::vector<ColumnFamilyHandle*>& handles) {
+    const std::vector<ColumnFamilyHandle*>& handles,
+    bool check_exist) {
   std::unique_lock<std::mutex> lock(thread_list_mutex_);
-  assert(cf_info_map_.size() == handles.size());
+  if (check_exist) {
+    assert(cf_info_map_.size() == handles.size());
+  }
   for (auto* handle : handles) {
     auto* cfd = reinterpret_cast<ColumnFamilyHandleImpl*>(handle)->cfd();
     auto iter __attribute__((unused)) = cf_info_map_.find(cfd);
-    assert(iter != cf_info_map_.end());
-    assert(iter->second);
-    assert(iter->second->cf_name == cfd->GetName());
+    if (check_exist) {
+      assert(iter != cf_info_map_.end());
+      assert(iter->second);
+      assert(iter->second->cf_name == cfd->GetName());
+    } else {
+      assert(iter == cf_info_map_.end());
+    }
   }
 }
 }  // namespace rocksdb