如果在alert log有如下信息：
*** 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
原因：
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
该Bug 影响的2个版本：
10.2.0.5
11.2.0.1
在如下版本已经修复：
12.1 (Future Release)
11.2.0.2 (Server Patch Set)
10.2.0.5.2 Patch Set Update
10.2.0.5 Patch 1 on Windows Platforms
之前也将DB 升级到10.2.0.5了。 还没有遇到这个bug。 不过论坛里有人已经遇到了。 小关注一下。
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