Session hangs on "buffer busy waits"

  • From: "Nahata, Naveen" <Naveen.Nahata@xxxxxxxxxxxxxxx>
  • To: <ORACLE-L@xxxxxxxxxxxxx>
  • Date: Wed, 16 May 2007 18:14:36 -0400

Oracle Ebusiness Suite 11.5.10.2, 9.2.0.6 on Solaris 9 64-bit.

One of the workflow agent processes occassionally hangs. V$session_wait
shows state = 'WAITING', event = 'buffer busy waits' and seconds_in_wait
keep incrementing until I resolve it by flushing the buffer cache. Since
the session holds multiple locks on key application tables, almost all
the sessions hang waiting on "enqueue".

I tracked down the block to AQ$_WF_JAVA_DEFERRED_I table. 

Has anyone seen anything similar? Any ideas on how I can debug it
further?

I've seen performance issues with the AQ tables before and am thinking
of rebuilding the queues and reorganizing the objects. Hopefully this
will alleviate the problem. 

Naveen



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