From 006a764df9a9f1456555c6902b238c2ddb04c684 Mon Sep 17 00:00:00 2001
From: Alexey Zatelepin <ztlpn@yandex-team.ru>
Date: Wed, 9 Jan 2019 20:52:25 +0300
Subject: [PATCH] don't use pool for TaskStatsInfoGetter [#CLICKHOUSE-4209]

Pool is not needed because creation of a TaskStatsInfoGetter takes
an order of 10us. Also pool is harmful because created sockets are
never closed.
---
 dbms/src/Common/CurrentThread.cpp | 3 ---
 dbms/src/Common/ThreadStatus.cpp  | 5 +----
 dbms/src/Common/ThreadStatus.h    | 4 +---
 3 files changed, 2 insertions(+), 10 deletions(-)

diff --git a/dbms/src/Common/CurrentThread.cpp b/dbms/src/Common/CurrentThread.cpp
index a3919108724..b2f165e5469 100644
--- a/dbms/src/Common/CurrentThread.cpp
+++ b/dbms/src/Common/CurrentThread.cpp
@@ -3,7 +3,6 @@
 #include "CurrentThread.h"
 #include <common/logger_useful.h>
 #include <Common/ThreadStatus.h>
-#include <Common/ObjectPool.h>
 #include <Common/TaskStatsInfoGetter.h>
 #include <Interpreters/ProcessList.h>
 #include <Interpreters/Context.h>
@@ -24,8 +23,6 @@ namespace ErrorCodes
     extern const int LOGICAL_ERROR;
 }
 
-SimpleObjectPool<TaskStatsInfoGetter> task_stats_info_getter_pool;
-
 // Smoker's implementation to avoid thread_local usage: error: undefined symbol: __cxa_thread_atexit
 #if defined(ARCADIA_ROOT)
 struct ThreadStatusPtrHolder : ThreadStatusPtr
diff --git a/dbms/src/Common/ThreadStatus.cpp b/dbms/src/Common/ThreadStatus.cpp
index 7a321cdaeb7..0ee09d527ce 100644
--- a/dbms/src/Common/ThreadStatus.cpp
+++ b/dbms/src/Common/ThreadStatus.cpp
@@ -21,9 +21,6 @@ namespace ErrorCodes
 }
 
 
-extern SimpleObjectPool<TaskStatsInfoGetter> task_stats_info_getter_pool;
-
-
 TasksStatsCounters TasksStatsCounters::current()
 {
     TasksStatsCounters res;
@@ -74,7 +71,7 @@ void ThreadStatus::initPerformanceCounters()
         if (TaskStatsInfoGetter::checkPermissions())
         {
             if (!taskstats_getter)
-                taskstats_getter = task_stats_info_getter_pool.getDefault();
+                taskstats_getter = std::make_unique<TaskStatsInfoGetter>();
 
             *last_taskstats = TasksStatsCounters::current();
         }
diff --git a/dbms/src/Common/ThreadStatus.h b/dbms/src/Common/ThreadStatus.h
index 822e1931447..3f7a91a54f0 100644
--- a/dbms/src/Common/ThreadStatus.h
+++ b/dbms/src/Common/ThreadStatus.h
@@ -2,7 +2,6 @@
 
 #include <Common/ProfileEvents.h>
 #include <Common/MemoryTracker.h>
-#include <Common/ObjectPool.h>
 
 #include <IO/Progress.h>
 
@@ -175,8 +174,7 @@ protected:
     std::unique_ptr<TasksStatsCounters> last_taskstats;
 
     /// Set to non-nullptr only if we have enough capabilities.
-    /// We use pool because creation and destruction of TaskStatsInfoGetter objects are expensive.
-    SimpleObjectPool<TaskStatsInfoGetter>::Pointer taskstats_getter;
+    std::unique_ptr<TaskStatsInfoGetter> taskstats_getter;
 };
 
 }