19c: Duplicate PQ workers created at instance level (Doc ID 2719466.1)

Last updated on APRIL 17, 2023

Applies to:

Symptoms

This is a  6 node RAC on Exadata. There are many duplicated PQ worker processes with the same process name, the one with most processes is

<db_name>_p00e_<instance_name1>:

$ ps -ef|grep <db_name> |grep p0|wc
    258    2083   17560
    
$ ps -ef|grep ora_p00e_<instance_name1> |grep -v grep |wc
     79     632    5293
    

Because of this PQ query keeps getting downgraded to serial on instance 1.

There are many duplicate PQ processes on node 1. Because of this a job with parallel hint of 64 kept downgraded to serial on inst 1 due to no available PQ process, but there isn't other SQL using PQ at that time.

Changes

Cause

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