【轉】WARNING:Could not lower the asynch I/O limit 錯誤

轉自：http://djb1008.itpub.net/post/42280/518420

一. 問題描述

在AIX 6.1+ORACLE 10.2.0.5 的多個資料庫的udump,bdump 目錄產生了多個trace檔案,不斷報警告:

WARNING:Could not lower the asynch I/O limit to 6144 for SQL direct I/O. It is set to -1

二. 問題分析

在metalink上搜尋'WARNING:Could not lower the asynch I/O limit to',找到了一篇文章

"WARNING:Could not lower the asynch I/O limit to 224 for SQL direct I/O. It is set to -1" After Upgrading To 10.2.0.5 [ID 1155445.1]",其內容如下:

This document is being delivered to you via Oracle Support's Rapid Visibility (RaV) process and therefore has not been subject to an independent technical review.

Applies to:

Oracle Server - Enterprise Edition - Version: 10.2.0.5 and later [Release: 10.2 and later ]

This problem can occur on any platform.

Symptoms

Warning below appears after upgrading to 10.2.0.5

*** SESSION ID:(538.48) 2010-07-15 08:41:30.649

WARNING:Could not lower the asynch I/O limit to 224 for SQL direct I/O. It is set to -1

WARNING:Could not lower the asynch I/O limit to 192 for SQL direct I/O. It is set to -1

WARNING:Could not lower the asynch I/O limit to 224 for SQL direct I/O. It is set to -1

WARNING:Could not lower the asynch I/O limit to 192 for SQL direct I/O. It is set to -1

WARNING:Could not lower the asynch I/O limit to 160 for SQL direct I/O. It is set to -1

Changes

Recently upgraded to 10.2.0.5.

Cause

This seems due to bug 9772888 10.2.0.5 RDBMS 10.2.0.5 BUFFER CACHE PRODID-5 PORTID-23 Abstract: WARNING:COULD NOT LOWER THE ASYNCH I/O LIMIT TO 160 FOR SQL DIRECT I/O. IT IS SE

Same behavior. appears and on the same platform. 10.2.0.5

Solution

1. Upgrade to Oracle 11.2 and install on top patchset 11.2.0.2.0 (or higher version patchset) where issue is fixed

OR

2. Install one-off patch on top of 10.2.0.5.0 if available to your platform.

References

- WARNING:COULD NOT LOWER THE ASYNCH I/O LIMIT TO 160 FOR SQL DIRECT I/O. IT IS SE

三.問題解決

當前資料庫因為應用系統的問題,不方便升級到11.2.0.2,這裡採用打9772888 補丁的方法來解決.

問題解決操作步驟

1.在metalink上下載補丁p9772888_10205_AIX64-5L.zip

2.停止資料庫例項,使用opatch升級補丁

3.啟動資料庫例項,檢查報警資訊不再出現,問題得到解決

另外:

如果是rac環境,需要執行下面的步驟:

1. Stop instances running on node 1.

2. Run 'opatch apply /9772888' on node 1.

3. When the apply finishes, opatch asks for confirmation

before going on to apply the patch to node 2.

4. Start instances on node 1.

5. Stop instances running on node 2.

6. Ask opatch to continue to applying the patch to node 2.

7. Start instances on node 2.