RE: 11.2.0.3 SQL Profile Confusion
- From: Christian Antognini <Christian.Antognini@xxxxxxxxxxxx>
- To: "christopherdtaylor1994@xxxxxxxxx" <christopherdtaylor1994@xxxxxxxxx>
- Date: Sat, 2 Nov 2013 10:14:56 +0000
Hi
> However I'm confused why it would even recommend a parallel query profile
> based on the above information?
>
> Also, when I tested it out, elapsed time jumped from 1.8 Seconds to 26.845
> seconds per execution and used 32 parallel processors!
IMO, in most situations, it's not sensible to run in parallel SQL statements
that have a response time of few seconds.
I already saw cases where the STA advise such SQL profiles. Hence, you are not
alone ;-) I would probably delete them.
> (I definitely understand this - way too many parallel processes and the
> overhead
> involved increased the total execution time).
This is probably because I/O calibration statistics are not in place. Otherwise
the DOP would be much lower. If you want to keep the SQL profile, either you
run I/O calibration or you setup the resource manager to cap the DOP.
> Anyone want to help me understand why it came up with a Parallel SQL
> Profile recommendation in the first place?
To do so you have to provide lot of information...
HTH
Chris Antognini
Troubleshooting Oracle Performance, Apress 2008
http://top.antognini.ch
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