解放されないIOCPリスナー


11

「Non-yielding IOCP Listener」が何を示しているか誰か知っていますか?

私たちのSQL Serverにはバグチェックダンプがありました。

=====================================================================                                            
       BugCheck Dump                                                                                             
=====================================================================                                            

This file is generated by Microsoft SQL Server                                                                   
version 9.00.5292.00                                                                                             
upon detection of fatal unexpected error. Please return this file,                                               
the query or program that produced the bugcheck, the database and                                                
the error log, and any other pertinent information with a Service Request.                                       


Computer type is AT/AT COMPATIBLE.                                                                               
Bios Version is DELL   - 1                                                                                       
Phoenix ROM BIOS PLUS Version 1.10 1.5.2                                                                         
Current time is 23:01:04 09/07/12.                                                                               
48 Unknown CPU 9., 2 Mhz processor (s).                                                                          
Windows NT 6.1 Build 7601 CSD Service Pack 1.                                                                    

Memory                               
MemoryLoad = 81%                     
Total Physical = 524278 MB           
Available Physical = 97549 MB        
Total Page File = 524276 MB          
Available Page File = 94472 MB       
Total Virtual = 8388607 MB           
Available Virtual = 7846765 MB       
**Dump thread - spid = 0, PSS = 0x0000000000000000, EC = 0x0000000000000000                                      
***Stack Dump being sent to C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\LOG\SQLDump0008.txt              
* *******************************************************************************                                
*                                                                                                                
* BEGIN STACK DUMP:                                                                                              
*   09/07/12 23:01:04 spid 0                                                                                     
*                                                                                                                
* Non-yielding IOCP Listener                                                                                     
*                                                                                                                
* *******************************************************************************             </pre>                   


SQLDump0008.log contains:

<pre>
 No user action is required.
2012-09-07 18:30:11.28 spid782     Recovery of any in-doubt distributed transactions involving Microsoft Distributed Transaction Coordinator (MS DTC) has completed. This is an informational message only. No user action is required.
2012-09-07 20:58:54.53 spid196     The alert for 'average delay' has been raised. The current value of '509' surpasses the threshold '100'.
2012-09-07 20:59:24.74 spid477     The alert for 'average delay' has been raised. The current value of '299' surpasses the threshold '100'.
2012-09-07 21:44:06.53 spid23s     Database mirroring is inactive for database 'ToDoLists'. This is an informational message only. No user action is required.
2012-09-07 21:44:06.59 spid456     The alert for 'average delay' has been raised. The current value of '518' surpasses the threshold '100'.
2012-09-07 21:44:57.98 spid425     Error: 18056, Severity: 20, State: 27.
2012-09-07 21:44:57.98 spid425     The client was unable to reuse a session with SPID 425, which had been reset for connection pooling. This error may have been caused by an earlier operation failing. Check the error logs for failed operations immediately before this error message.
2012-09-07 21:44:57.98 spid808     Error: 18056, Severity: 20, State: 27.
2012-09-07 21:44:57.98 spid808     The client was unable to reuse a session with SPID 808, which had been reset for connection pooling. This error may have been caused by an earlier operation failing. Check the error logs for failed operations immediately before this error message.
2012-09-07 21:44:58.01 spid155     Error: 18056, Severity: 20, State: 27.
2012-09-07 21:44:58.01 spid155     The client was unable to reuse a session with SPID 155, which had been reset for connection pooling. This error may have been caused by an earlier operation failing. Check the error logs for failed operations immediately before this error message.
2012-09-07 21:44:58.03 spid486     Task (Worker 0x00000001B93B21C0) was forced to yield 2 times: 
2012-09-07 21:44:58.04 spid65s     Database mirroring is inactive for database 'Tracking'. This is an informational message only. No user action is required.
2012-09-07 21:44:58.06 spid486     Task (Worker 0x0000000CB9B341C0) was forced to yield 8 times: 
2012-09-07 21:44:58.09 spid486     Task (Worker 0x0000000655A9E1C0) was forced to yield 3 times: 
2012-09-07 21:44:58.10 spid486     Task (Worker 0x00000006C03BE1C0) was forced to yield 8 times: 
2012-09-07 21:44:58.11 spid65s     Error: 1404, Severity: 16, State: 6.
2012-09-07 21:44:58.11 spid65s     The command failed because the database mirror is busy. Reissue the command later.
2012-09-07 21:44:58.11 spid486     Task (Worker 0x0000000C819D01C0) was forced to yield 2 times: 
2012-09-07 21:44:58.49 spid140     The alert for 'average delay' has been raised. The current value of '191' surpasses the threshold '100'.
2012-09-07 21:45:00.66 spid46s     SQL Server has encountered 6 occurrence(s) of cachestore flush for the 'Object Plans' cachestore (part of plan cache) due to some database maintenance or reconfigure operations.
2012-09-07 21:45:17.25 spid83s     SQL Server has encountered 6 occurrence(s) of cachestore flush for the 'SQL Plans' cachestore (part of plan cache) due to some database maintenance or reconfigure operations.
2012-09-07 21:45:17.25 spid54s     SQL Server has encountered 6 occurrence(s) of cachestore flush for the 'Bound Trees' cachestore (part of plan cache) due to some database maintenance or reconfigure operations.
2012-09-07 21:45:17.28 spid45s     The mirrored database "Tracking" is changing roles from "PRINCIPAL" to "MIRROR" due to Role Syncronization.
2012-09-07 21:45:17.61 spid46s     Bypassing recovery for database 'Tracking' because it is marked as a mirror database, which cannot be recovered. This is an informational message only. No user action is required.
2012-09-07 21:45:29.21 spid45s     Database mirroring is active with database 'Tracking' as the mirror copy. This is an informational message only. No user action is required.
2012-09-07 21:50:56.94 spid196s    SQL Server has encountered 5 occurrence(s) of cachestore flush for the 'Object Plans' cachestore (part of plan cache) due to some database maintenance or reconfigure operations.
2012-09-07 21:50:57.14 spid196s    SQL Server has encountered 5 occurrence(s) of cachestore flush for the 'SQL Plans' cachestore (part of plan cache) due to some database maintenance or reconfigure operations.
2012-09-07 21:50:57.14 spid196s    SQL Server has encountered 5 occurrence(s) of cachestore flush for the 'Bound Trees' cachestore (part of plan cache) due to some database maintenance or reconfigure operations.
2012-09-07 23:00:09.42 spid438     Error: 18056, Severity: 20, State: 27.
2012-09-07 23:00:09.42 spid438     The client was unable to reuse a session with SPID 438, which had been reset for connection pooling. This error may have been caused by an earlier operation failing. Check the error logs for failed operations immediately before this error message.
2012-09-07 23:01:04.26 Server      Using 'dbghelp.dll' version '4.0.5'
2012-09-07 23:01:04.29 Server      **Dump thread - spid = 0, PSS = 0x0000000000000000, EC = 0x0000000000000000
2012-09-07 23:01:04.29 Server      ***Stack Dump being sent to C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\LOG\SQLDump0008.txt
2012-09-07 23:01:04.29 Server      * *******************************************************************************
2012-09-07 23:01:04.29 Server      *
2012-09-07 23:01:04.29 Server      * BEGIN STACK DUMP:
2012-09-07 23:01:04.29 Server      *   09/07/12 23:01:04 spid 0
2012-09-07 23:01:04.29 Server      *
2012-09-07 23:01:04.29 Server      * Non-yielding IOCP Listener
2012-09-07 23:01:04.29 Server      *
2012-09-07 23:01:04.29 Server      * *******************************************************************************
2012-09-07 23:01:04.29 Server      * -------------------------------------------------------------------------------
2012-09-07 23:01:04.29 Server      * Short Stack Dump
2012-09-07 23:01:04.33 spid73      The alert for 'average delay' has been raised. The current value of '304' surpasses the threshold '100'.
2012-09-07 23:01:04.34 Server      Stack Signature for the dump is 0x00000000000002E8

「平均遅延」メッセージのアラートはデータベースミラーリングに関連し、トランザクションのコミットにかかる時間が指定された時間を超えると発生するアラートです。is_event_logged「平均遅延」アラートの列は0です。

あなたはからの出力を見ることができるsys.configurationsフェイルオーバー後、タイムアウトにミラーリングセッションを引き起こす可能性がありますか?

回答:


9

IOCPはI / O完了ポートです。解放されないIOCPリスナーとは、IO完了ルーチンを処理するスレッドが何かを実行するのに(比較的)非常に長い時間を要し、SQLOSがスタック/ハングアップ/何であっても実行できることを意味します。

SQLサーバーは、多くのASYNC IOを実行します。それが動作する方法は、OSにIO要求を送信するとき、「このIOを非同期で実行します。これが完了すると呼び出す関数ポインターがあります」と表示されます。

呼び出される関数は、IO完了リスナーです。

ディスクから読み取られたページについて考えます。選択を実行するスレッドは、メモリにないページを読み取る必要があります。PAGEIOLATCHを取り、非同期IOをウィンドウに発行してページを読み取り、スリープ状態になります。

OSがIOを完了すると、IOに「完了」のフラグを付けるIOCP関数を呼び出します。その後すぐに、SQLスレッドは4ミリ秒のクォンタムを終了し、処理するIOをチェックします。完了のフラグを立て、発行スレッドにウェイクアップするように通知します。SELECTスレッドがスケジュールされ、PAGEIOLATCHが解放され、良好な状態です。

現在、IOCPが実行する作業量は、関連するIOのタイプによって異なります。私は、DBミラーリングを使用すると、ページをバッファー・プールに読み取るだけの場合よりも多くの作業を行うと思います。

SQLサーバーで作業しているプログラマーであり、DBミラーリングコードを最適化したい場合、IOOSミラーリングコードパスとSQLOSシステムスレッドコードパスでより多くの作業を行いたくなるかもしれません。

あるいは、IOCPはデータを固定サイズのミラーリングバッファーにコピーする必要があり、それが完了するまでループに留まります。

または、<>が発生し、IOCP機能が「スタック」している可能性があります。

フェイルオーバー中に発生し、多くのLOGアクティビティが発生した場合、これについては心配しません。一貫して発生する場合は、さらに調査が必要な場合があります。

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