In this Document   Purpose   Troubleshooting Steps   What is a 'library cache: mutex X' wait?   What causes 'library cache: mutex X' wait?   Name of events in 12c and higher   How to diagnose the cause.   How to Examine the Diagnostics.   Potential S…

What is a 'library cache: mutex X' wait? The mutex feature is a mechanism to control access to in memory structures. It is used in a number of areas including the library cache. The library cache is a memory area that holds parsed cursor structures n…

我们先来看看 library cache: mutex X . 是个什么东西 The library cache mutex is acquired for similar purposes that the library cache latches were acquired in prior versions of Oracle. In 10g, mutexes were introduced for certain operations in the library cache. Sta…

11g等待事件之library cache: mutex X 作者: dbafree 日期: 2012 年 07 月 01 日发表评论 (0)查看评论   library cache: mutex X替代了之前的library cache latch,主要作用是在hash bucket中定位handle时使用.(比如SQL硬解析时,需要往hash bucket中新增一个cursor时,需要library cache latch).如下图所示:文档上面的解释如下:The library cache…

[20190402]Library Cache mutex.txt 1.环境:SCOTT@book> @ ver1PORT_STRING                    VERSION        BANNER------------------------------ -------------- --------------------------------------------------------------------------------x86_64/Linux 2.…

业务系统数据库夯住,数据库内大量的library cache: mutex X及latch: shared pool等待,alert日志信息如下 Tue Sep :: WARNING: inbound connection timed out (ORA-) Tue Sep :: WARNING: inbound connection timed out (ORA-) Tue Sep :: WARNING: inbound connection timed out (ORA-) Tue Sep :…

Doc ID 1476663.1) To Bottom In this Document   Purpose   Troubleshooting Steps   Brief Definition:   Problem Confirmation:   Library Cache Pin   Cursor Pin S wait on X   Improving Performance of Library cache pin or Pin S wait on X   Measuring Succes…

这两个等待事件其实很少出现在top5列表中,一般都没什么印象,在此整理记录以便以后查阅. 常见的library cache lock产生的原因在<高级OWI与Oracle性能调查>这本书和下面这个文档中有一般性的描述: Troubleshooting Library Cache: Lock, Pin and Load Lock (Doc ID 444560.1) 一般可以理解的是alter table或者alter package/procedure会以X模式持有library cache l…

My colleague suddenly encountered a problem today,a Database becomes very slow , and the a lot of session wait library cache lock event, Let me help him to look. DB env is 10.2.0.4 rac. at first ,to generate a AWR manually. exec dbms_workload_reposit…

我们都知道可是使用 alter system flush shared_pool 来清除shared pool 信息,当时不能指定清除某个对象.因为在系统繁忙的时侯 使用 alter system flush shared_pool  是很危险的, 在oracle 10.2.0.4 以及 11g 有了新的方法.提供的DBMS_SHARED_POOL.PURGE 程序来完成. 不过需要注意一点,在10.2.0.4中,虽然PURGE过程已经存在,但是要使这个过程可以真正的生效,还必须设置一个EVEN…