Re: converting from non-rac to rac performance issue
- From: "Greg Rahn" <greg@xxxxxxxxxxxxxxxxxx>
- To: ksmadduri@xxxxxxxxx
- Date: Wed, 10 Dec 2008 13:57:44 -0800
On Tue, Dec 9, 2008 at 5:45 PM, Kumar Madduri <ksmadduri@xxxxxxxxx> wrote:
> We are observing performance issues with high amount of elapsed time for
> dbfile sequential read.
Does this mean that the reads are taking longer or that your Top 5 in
AWR is now reporting this event, more than previously.
There could be two causes here: first that reads are taking longer,
the second, that execution plans have changed and now more reads are
being issued, but they are not necessarily slow(er). You need to
determine the root cause.
> The same job before upgrade completes in 3hrs50mins but now taking 5hours.
> We did take the tkprof output and notice high amount of dbfile sequential
> reads/scattered reads.
> After we applied the patch 7243560 - RAPID INCREASE IN DBFILE SEQUENTIAL
> READ AFTER MOVING TO ASM the job has completed in 4hrs 30mins.
>
> Almost all queries run twice the time it runs on single instance NON-RAC
> NON-ASM all storage on DMX.
How do the metrics differ? How long are the reads taking?
What OS?
--
Regards,
Greg Rahn
http://structureddata.org
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