4031 PX msg pool

Multiple ORA-4031 Errors Of Reducing Sizes For "PX msg pool" In The Large Pool (Doc ID 1515877.1)

Oracle Database - Enterprise Edition - Version 11.1.0.7 to 11.2.0.3 [Release 11.1 to 11.2]
Information in this document applies to any platform.

SYMPTOMS

The alert file contains several ORA-4031 errors from a single process on the large pool with reducing allocation sizes, as in:

Mon Dec 10 10:11:17 2012
Errors in file /u01/apps/oracle/diag/rdbms/orcl/orcl/trace/orcl_ora_4457026.trc (incident=6937670):
ORA-04031: unable to allocate 2048024 bytes of shared memory ("large pool","unknown object","large pool","PX msg pool")
Incident details in: /u01/apps/oracle/diag/rdbms/orcl/orcl/incident/incdir_6937670/orcl_ora_4457026_i6937670.trc
Mon Dec 10 10:11:21 2012
Errors in file /u01/apps/oracle/diag/rdbms/orcl/orcl/trace/orcl_ora_4457026.trc (incident=6937671):
ORA-04031: unable to allocate 1024024 bytes of shared memory ("large pool","unknown object","large pool","PX msg pool")
Incident details in: /u01/apps/oracle/diag/rdbms/orcl/orcl/incident/incdir_6937671/orcl_ora_4457026_i6937671.trc

CAUSE

The cause of this problem has been identified in:
unpublished Bug:13072654 - ORA-4031 CANT ALLOC 14MB IN LARGE POOL, PX MSG POOL

This is due to the ORA-4031 errors being reported externally, when they should not be. The reducing sizes indicate that the algorithm is attempting to request a smaller amount of memory, given that the larger request failed. The ORA-4031 errors for the memory allocation PX msg pool should not be reported in these circumstances.

Bug:13072654 is fixed in RDBMS 12.1.

SOLUTION

To implement a solution for Bug:13072654, please execute any of the below alternative solutions:

• Upgrade to 12.1 when it will become available
  
  OR

• Apply patchset release 11.2.0.4 when it becomes available (not available as of time of publishing this article: MAR-2013) in which Bug:13072654 is fixed.
  
  OR

• Download and apply interim Patch:13072654, if available for your platform and RDBMS release. To check for conflicting patches, please use the MOS Patch Planner Tool. If no patch is available, file a Service Request through My Oracle Support for your specific Oracle version and platform.