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QMON Worker Process (Q00X) Leaks Memory in or Generates : ORA-4030 (Doc ID 1379309.1)

Last updated on AUGUST 04, 2021

Applies to:

Oracle Database - Enterprise Edition - Version to [Release 10.2]
Oracle Database Cloud Schema Service - Version N/A and later
Gen 1 Exadata Cloud at Customer (Oracle Exadata Database Cloud Machine) - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Information in this document applies to any platform.


Having applied the Oracle Server patchset, the qmon worker process : Q00X is observed either to show increasing memory usage as is detailed in the v$process view or will fail with the error Ora-4030.

This has the same profile as : 6009358 which is supposedly fixed in

Note : in order to diagnose / confirm this issue , it is necessary to set the following event prior to obtaining a heap dump of the process; furthermore the instance needs to be stopped and restarted for theevent to take affect :
- 10235 / level 65536

All the above event does is ensure that the mnemonic linked with a permanent memory chunk allocation is output in the trace file produced.

This is not done if the event is not set.

A heapdump of the qmon worker leaking memory can then be generated using :

sqlplus "/ as sysdba"
oradebug setospid X  (X is the os process id of the qmon worker)
oradebug unlimit
oradebug dump heapdump level 268435485

The above shows significant memory allocations connected with :

"kprbalo temp me" and "CPM trailer" chunk allocations




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