Severe library cache latch contention with DB Control job

From: Rich Jesse <>
Date: Tue, 1 Dec 2009 10:01:06 -0600 (CST)
Message-ID: <>

Hey all,

I've noticed a condition twice in 10 days with our DB on AIX where library cache latch contention was severe. Each incident I now believe was caused by the EMD_MAINTENANCE.EXECUTE_EM_DBMS_JOB_PROCS job -- a leftover from Database Control that I inherited but replaced with Grid Control over two years ago. Apparently, I was also supposed to kill this job, which I now have done. But two things still bug me.

First, according to Grid Control, this job was launched by SYSMAN but somehow changed it's session owner to *my* username. I haven't experimented with this other than the technique used in exp/imp scripts -- thoughts? Why me?

Second, what could this job have done to cause severe library cache latch contention? It was bad enough the first time to somehow crash the DBMS_STATS job that was running with an "ORA-20000: Unable to analyze TABLE "MYSCHEMA"."MYTABLE", insufficient privileges or does not exist" error.

The job will never run again, but I'm trying to learn as much as I can about it for future reference.


p.s. No references to this job in the list archives, a Google search turned up a mixed bag of half-complete ideas and a now-non-existent MOS (nee Metalink) article, and of course not much on MOS, either.

Received on Tue Dec 01 2009 - 10:01:06 CST

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