Re: Urgent rac wait problem

From: Yechiel Adar <adar666_at_inter.net.il>
Date: Mon, 16 Mar 2009 08:43:27 +0200
Message-id: <49BDF50F.7050604_at_inter.net.il>

Problem solved.
We did compute statistics with histograms on the table and now it works fine on both machines.

It turned out that the second node is NOT the same. It has 4 CPU and 4 GB of memory instead of 8 CPU and 8 GB of memory in node 1. This probably had effect on the explain plan and used less efficient path to the data.

Adar Yechiel
Rechovot, Israel

Riyaj Shamsudeen wrote:
> Adar
> You might want to look at the plan for that SQL on node 2. May be
> the execution plan is different in node 2 compared to node 1. This
> scenario is possible due to difference in instance parameters.
> Can you also print tkprof output wait lines from node 2? I am
> specifically interested in seeing Interconnect performance numbers.
> What is the average time taken for 'gc current block 2 way'?
> What is your average block receive time and average send time from
> AWR reports during this time frame ? That might provide more insights too.
>
> --
> Cheers
>
> Riyaj Shamsudeen
> Principal DBA,
> Ora!nternals - http://www.orainternals.com
> Specialists in Performance, Recovery and EBS11i
> Blog: http://orainternals.wordpress.com
>
> On Sun, Mar 15, 2009 at 4:55 AM, Yechiel Adar <adar666_at_inter.net.il
> <mailto:adar666_at_inter.net.il>> wrote:
>
> Update:
> This happens only when the user connects to node 2.
> I went a little crazy as I run the same sql from my station and it
> worked fine.
> After I took 10046 trace I saw that their trace was on node 2 and
> mine was on node 1.
> When I removed the load_balance parameter from the tnsnames, so
> they will always connect to node 1, the problem went away.
>
> So the problem is not so urgent but I would like to work with load
> balance.
>
> Adar Yechiel
> Rechovot, Israel
>
>
>
>
> Yechiel Adar wrote:
>
> We moved from one node rac to 2 node rac.
> A simple query takes 9 seconds instead of 0.3 second.
>
> The user activated 10046 trace and I see a lot of "gc current
> block 2-way".
>
> Help urgently required.
>
> Adar Yechiel
> Rechovot, Israel
>
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Received on Mon Mar 16 2009 - 01:43:27 CDT