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Re: Parallelism in oracle8i

From: Scott <oraracdba_at_yahoo.com>
Date: Thu, 30 Aug 2001 14:43:09 -0700
Message-ID: <F001.0037E460.20010830145132@fatcity.com>

Soman, If you are truly scanning 100,000 records then that could be the problem. There is overhead to do the PQ. In your case it is probably cheaper to do a serialized query. Try the same test with 1,000,000 or 2,000,000 records and you will probably see a difference. I had a similar problem to this in an OPS environment. I would do a PQ with 500,000 records on one node and it would take about 10 seconds but the same PQ across nodes would take 15 seconds. However when I bumped the number of records to around 2,000,000 the PQ on 1 node would take about 25 seconds and the PQ across nodes took about 19 seconds. There is a cost to PQ and you have to find where PQ's start to outperform the serialized queries. I would try this before staring complex tuning rituals.

Scott


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Author: Scott
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Received on Thu Aug 30 2001 - 16:43:09 CDT

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