Grid Control Performance: High 'Ul Contention' Seen for the Repository Database Sessions (Doc ID 862527.1)

Last updated on AUGUST 27, 2013

Applies to:

Enterprise Manager Base Platform - Version 10.2.0.5 to 10.2.0.5 [Release 10.2]
Information in this document applies to any platform.
Checked for relevance on 27-Aug-2013

Symptoms

Login to Grid Console and navigate to Targets -> Databases -> click on Repository Database -> Performance. The following are noticed:

-  From Performance "Top Activity" for the Repository, there is a significant amount of "Application Waits".

-  There are many (around 10) Active Sessions by OMS under the "Top Sessions".

-  The "Top SQL" is:

BEGIN EMDW_LOG.set_context(MGMT_JOB_ENGINE.MODULE_NAME, :1); BEGIN
MGMT_JOB_ENGINE.process_wait_step(:2);END; EMDW_LOG.set_context; END;


The "SQL Details" for this SQL shows significant "enq:UL - contention".

The "Statistics" for this SQL shows the Module is
"OEM.CacheModeWaitPool" with "Application Waits" taking up approximately 95% of "Activity by Waits".

Note: enq:UL - contention "translates" to Application "PL/SQL User Lock"


The EMDiag (repvfy) report from the repository shows there are 1000+ jobs shown for the Jobs test
116. Stuck wait executions


Changes

OMS has recently been uprgaded from 10.2.0.4 to 10.2.0.5.

Cause

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