Nested loop very slow

From: Daemen, Remco <R.Daemen_at_facent.nl>
Date: Thu, 23 Aug 2001 04:01:11 -0700
Message-ID: <F001.00374D07.20010823035620@fatcity.com>

Hi,

I'm joining a table with 32000 rows with a very large table (3 Gb), resulting in 97000 records. When I execute the query without hints, it uses a full table scan and a hash join, and returns a result in 4 minutes. When I use a hint forcing a nested loop (and part of an index (range scan)), the query takes 14 minutes to complete. The question is: why does a join between an inner table with 32000 records and a large table using a range scan on an index take so long ? I would expect Oracle to give a result within seconds, a few minutes tops !

The table has very few chained rows and I've rebuilt the index recently. RDBMS is 8.1.6. Index and data are divided over many different disks.

Any suggestions ? Except kicking the server ?

Remco

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Author: Daemen, Remco
  INET: R.Daemen_at_facent.nl

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