Bug 9239863 - Excessive "library cache:mutex X" contention on hot objects (文档 ID 9239863.8)
2014-01-18 19:45
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Bug 9239863 Excessive "library cache:mutex X" contention on hot objects
This note gives a brief overview of bug 9239863.The content was last updated on: 28-JUN-2013
Click here for details of each of the sections below.
Affects:
Product (Component) | Oracle Server (Rdbms) |
Range of versions believed to be affected | Versions BELOW 12.1 |
Versions confirmed as being affected | 11.2.0.1 11.1.0.7 |
Platforms affected | Generic (all / most platforms affected) |
Fixed:
This issue is fixed in | 12.1.0.1 (Base Release) 11.2.0.2 (Server Patch Set) 11.2.0.1 Bundle Patch 6 for Exadata Database |
Symptoms: | Related To: |
Code Improvement Mutex Contention Waits for "library cache: mutex X" | _kgl_hot_object_copies _KGL_DEBUG |
Description
When there is *true* contention on a specific library cache object then performance of the instance might be bottlenecked on "library cache: mutex X" waits for that object. This fix is really an enhancement to allow specific objects which are known to exhibit high contention to be marked such that the contention can be reduced (by holding multiple copies of the object in the library cache). Rediscovery Notes: The following query may help identify objects being accessed heavily: select KGLNAOBJ, KGLNAOWN, KGLHDNSP, KGLOBTYP, KGLOBT23, KGLOBT24 from x$kglob where KGLOBT23 > 1000000 or KGLOBT24 > 1000000 order by KGLOBT24; Note: This fix requires special configuration via hidden parameters to have any effect. The fix should only be enabled under the guidance of Oracle Support.
Please note: The above is a summary description only. Actual symptoms can vary. Matching to any symptoms here does not confirm that you are encountering this problem. For questions about this bug please consult Oracle Support. |
References
Bug:9239863 (This link will only work for PUBLISHED bugs)Note:245840.1 Information on the sections in this article
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Database Products > Oracle
Database > Oracle
Database > Oracle
Database - Enterprise Edition
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