AQ Enqueue / Dequeue Benchmark on RAC 18.104.22.168 Shows Slowdown and Higher CPU
(Doc ID 1105624.1)
Last updated on FEBRUARY 26, 2019
Applies to:Oracle Database - Enterprise Edition - Version 22.214.171.124 and later
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Backup Service - Version N/A and later
Information in this document applies to any platform.
Performance issue affecting AQ applications where they have upgraded to 126.96.36.199 from 10.2.0.4; AQ activity is centred around enqueue / dequeue activity on a RAC environment.
It should be stated that most application are unlikely to be affected by the issues below .
Main observations :
- performance degradation with RAC is greater than with single instance;
slow down with single instance is also observed;
- commit activity appears to be taking longer;
- higher CPU observed;
- AWR report indicates higher statistic values in relation to the following for
the same test in 11g :
In the library cache activity ( RAC ) section of the AWR reports there is increased activity with respect to the following (same benchmark test) :
|statistic||10.2.0.4 value||188.8.131.52 value|
|ges pin requests||192||603829 ( TABLE )|
|ges messages sent||2423||5670|
|global enqueue gets sync||1312577||2315879|
|global enqueue releases||1309834||2313511|
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In this Document