oracle read by other session,AWR报告中，read by other session等待占88％，如何解决？

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于 2021-04-14 01:13:43 发布

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文章标签： oracle read by other session

在Oracle 10.2.0.4.0数据库中，AWR报告显示readbyothersession等待事件占据了88%，严重影响性能。问题源于多个会话重复读取相同数据块，尤其是全表扫描导致的热点块争用。虽然涉及的SQL执行频率正常，但效率低下。优化策略包括分析业务操作导致的热点数据，考虑内存大小是否合适，并调整SQL执行计划以减少重复读取。

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AWR报告中，read by other session等待占88％，如何解决？

中文社区 (MOSC)

数据库 (MOSC)

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Last updated on March 07, 2013

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ORACLE版本10.2.0.4.0

分析数据库AWR报告，Top 5 Timed Events 中，read by other session等待占88％，严重影响数据库性能。

看资料是指多个进程重复读同样的数据块导致的。可能涉及许多会话扫描同样的索引或者同时对一张表执行全表扫描。

数据库报告中，占用资源最多的是涉及大表全表扫描的很多SQL在执行，执行效率低(平常执行这些SQL比较快)，但是是业务正常使用的语句，执行频率大致是每小时执行300次左右，也正常。

这个问题，属于正常的业务导致的热点块争用，应该如何分析优化呢？和内存有没有关系(比如内存小)？

已经看过如下参考资料：

read by other session Definition: When information is requested from the database, Oracle will first read the data from disk into the database buffer cache. If two or more sessions request the same information, the first session will read the data into the buffer cache while other sessions wait.

In previous versions this wait was classified under the “buffer busy waits” event.

However, in Oracle 10.1 and higher this wait time is now broken out into the “read by other session” wait event.To view full details, sign in with your My Oracle Support Community account.

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