Re: risk: hangalalyze and system state
- From: Austin Hackett <hacketta_57@xxxxxx>
- To: oracle-l digest users <oracle-l@xxxxxxxxxxxxx>
- Date: Tue, 11 Feb 2014 21:01:10 +0000
Hi Jeremy
I have had a bad experience with system state dumps on Solaris 10 (SPARC) and
single instance 11.2.0.2.1.
This is going back a couple of years in a previous role, so sorry I can't
provide much detail.
It involved an investigation into a parent cursor memory leak bug. Support
asked me to take some system state dumps, which i did during a quiet time. This
was a pretty high volume system, so a fair amount going on even during quiet
periods. I'd scoured MOS for bugs involving system states dumps in my version,
asked the analyst for confirmation multiple times that it was safe to do this,
got clearance from management etc. Needless to say, within a minute or so of me
running for first command, there were monitoring dashboards glowing red and
application servers timing out. If I remember correctly, an exclusive mutex was
held whilst the dump was being written to disk leading to fairly severe system
hang. The feedback from support was that this kind of thing could happen in
rare circumstances (which wasn't what they told me when I first asked!)
I remember reading another 112.2 war story shortly afterwards:
http://oracledoug.com/serendipity/index.php?/archives/1645-Systemstate-Dump-warning.html
Unless things are totally hosed anyway, it's only something I'd do following a
thorough search of MOS for bugs and a discussion with relevant people about the
risk of taking the system state dump versus the impact/frequency of the issue
at hand and any possible workarounds.
Thanks
Austin
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