Martin Klier


Speaking at IOUG COLLABORATE 12: “Resolving child cursor issues resulting in mutex waits”

On April 22-26, 2012 the Independent Oracle Users Group (IOUG) is holding the COLLABORATE 12 forum in Mandalay Bay Convention Center, Las Vegas (US-NV).

The COLLABORATE is a widely known event in the Oracle Community, and attracts lots of Oracle guys and girls from all over the world. I feel honored to contribute a presentation about how to detect and resolve child cursor issues resulting in mutex wait events. It will be Lesson #893 as part of the “Oracle Internals & Performance Bootcamp”, which is maintained by Craig Shallahamer. Here comes the official excerpt from the IOUG session planner:


Thursday, April 26, 2012

#893 – „Resolving child cursor issues resulting in mutex waits“

Product Line:

Oracle Database 11gR2




In special situations, the Oracle Database generates too many child cursors for particular SQL-IDs. This results in high CPU load on the DB server, coming from heavy mutex access. This is visible as mutex wait events.

The lecture will show how this situation arises, how the DBA can try to quick-fix it and how long-term solutions can be found.

Additionally, we will have a closer look on the Oracle internal situation: Why does the DB use mutexes here, and how?


Martin Klier, Senior DBA
Klug GmbH integrierte Systeme


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