遇到WARNING:Could not lower the asynch I/O limit to 170 for SQL direct I/O. It is set to -1

该warning是在j001.trc文件里边的
平台信息如下（该信息也是来源于j001.trc文件）

Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
Windows NT Version V6.1 
CPU                 : 64 - type 8664, 32 Physical Cores

搜索mos,得到如下文章：

'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 (Doc ID 1155445.1)
Bug 9772888 - Needless "WARNING:Could not lower the asynch I/O limit to .. for SQL direct I/O It is set to -1" messages (Doc ID 9772888.8)

在上述文章中，该warning被定位为bug：

This seems due to 
Bug 9772888 - WARNING:COULD NOT LOWER THE ASYNCH I/O LIMIT TO 160 FOR SQL DIRECT I/O

Same behavior appears and on the same platform 10.2.0.5

当然，该bug并非针对windows平台：

解决该bug的方法：

Solution

To implement a solution for Bug:9772888, please execute any of the below alternative solutions:

• Upgrade to 11.2.0.2 or higher
  
  OR

• Download and apply interim Patch:9772888, if available for your platform and RDBMS release. To check for conflicting patches, please use the MOS Patch Planner Tool. For the Microsoft Windows platform this issue is fixed in patch bundle 1 and higher on top of the 10.2.0.5 release. If no patch is available, file a Service Request through My Oracle Support for your specific Oracle version and platform.

This issue is fixed in

12.1.0.1 (Base Release) 11.2.0.2 (Server Patch Set) 10.2.0.5.2 Database Patch Set Update 10.2.0.5 Patch 1 on Windows Platforms

这个案例也说明：打psu（非windows平台）或者bundle patch（windows平台）的重要性！