Performance diminishes over time on AIX 7.1 due to Large Segment Aliasing (Doc ID 1467807.1)

Last updated on APRIL 11, 2017

Applies to:

Oracle Server - Enterprise Edition - Version 10.2.0.1 to 11.2.0.3 [Release 10.2 to 11.2]
IBM AIX on POWER Systems (64-bit)

Symptoms

Database performance progressively degrades over time until the instance is restarted.
This could manifested by seeing the same SQL, with the same number of buffer get, s gradually  taking more and more CPU time, thereby increasing the overall elapsed time.  


This addition to CPU will show up under sys time and not user time as shown in the vmstat information bleow:

 

Cause

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