Re: Extremely Slow Query

From: Vladimir Begun <Vladimir.Begun_at_oracle.com>
Date: Fri, 03 Jan 2003 11:59:57 -0800
Message-ID: <F001.00526D21.20030103115957@fatcity.com>

Jonathan Lewis wrote:
> The problem is generic, the specific query
> isn't the point. RAC is a massive improvement
> on OPS because block transfer is by wire not
> disc - but it still takes a serious amount of
> time to fling blocks from node to node, especially
> if the blocks have been subject to very recent update
> at the remote nodes.

Thanks, Jonathan! Sorry for misunderstanding. Got it. I thought you are talking about this particular query -- "looks like you've hit the big problem with RAC" -- sounded like it was not before however it's here now. One of the main concept of RAC/OPS is understanding application(s) workload and assign/partition it to/among different nodes. So, here we have a good example of the (unavoidable) functional clash.

Raj, can you try this one:

SELECT /*+ LEADING(dba_types.t)

            INDEX(dba_types.o, i_obj3)
            INDEX(dba_types.so, i_obj3)
        */
        *

   FROM dba_types
/

In this case it's better to scan indexes.

> I like both your explanations for the size, and
> the unusual number of obj$ blocks that needed
> CR serving.

;)

-- 
Vladimir Begun
The statements and opinions expressed here are my own and
do not necessarily represent those of Oracle Corporation.

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Author: Vladimir Begun
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Received on Fri Jan 03 2003 - 13:59:57 CST