RE: Session With oper EXCL is also waiting - where to now? (systemstate dump)
- From: <Christopher.Taylor2@xxxxxxxxxxxx>
- To: <tanel@xxxxxxxxxxxxxx>
- Date: Wed, 19 Sep 2012 15:29:51 -0500
Thanks Tanel - I'm definitely looking into the bug aspect being 10.2.0.4
I've inherited a system that collects statistics every night for all tables and
runs for HOURS. I'm betting the contention happened between statistics and the
nightly batch processing hitting the same objects - but I'm still guessing
right now - trying to confirm by connecting all the dots.
Chris
From: tanel@xxxxxxxxxx [mailto:tanel@xxxxxxxxxx] On Behalf Of Tanel Poder
Sent: Wednesday, September 19, 2012 3:26 PM
To: Taylor Christopher - Nashville
Cc: oracle-l@xxxxxxxxxxxxx
Subject: Re: Session With oper EXCL is also waiting - where to now?
(systemstate dump)
Search for the address a5b6bd2a0 (case insensitive) in the systemstate dump
file. If some process still happened to be holding that latch while the dump
read its state object, it should dump out which one it was (and which session
state object was under it).
But allowing shared pool to automatically shrink is a bad idea in
super-critical latency-sensitive (OLTP) systems ... better "waste" some extra
memory for shared pool instead of having to live with CPU usage and share pool
latch/library cache mutex contention spikes...
Of course in your case the symptom was even more extreme (a hang), which may be
due to a bug ...
--
Tanel Poder
Blog - http://blog.tanelpoder.com
App - http://voic.ee
On Wed, Sep 19, 2012 at 11:01 PM,
<Christopher.Taylor2@xxxxxxxxxxxx<mailto:Christopher.Taylor2@xxxxxxxxxxxx>>
wrote:
(apologies for bad formatting - I'm trying to keep it simple tho)
(pastebin is blocked, but used gist https://gist.github.com/3751878)
3-node RAC 10.2.0.4
We had a "hang" last night from 2:50 to ~3:48 and Oracle was kind enough to
provide me with an automated system state dump.
(the bottom of this email is where I'm confused - where do I go from here?)
Looking at the ASH and AWR reports for the 2 hour window:
I see:
1.) An SGA Resize occurred:
Buffer Cache 30,608M increases to 30,656M
Shared Pool Size 5,136M *decreases* to 5,088M
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