Re: An ancient mystery
- From: Hemant K Chitale <hkchital@xxxxxxxxxxxxxx>
- To: oracledba.williams@xxxxxxxxx, "Oracle Discussion List" <oracle-l@xxxxxxxxxxxxx>
- Date: Sat, 22 Nov 2008 01:05:40 +0800
Is it a very complex query which joins with other tables hitting
OPTIMIZER_MAX_PERMUTATIONS because the potential execution operations
against *other* tables has changed (indexes dropped/created or
statistics updated on any of the other tables in the query) ?
At 11:05 AM Friday, Dennis Williams wrote:
List,
The situation:
Oracle <http://8.1.7.4>8.1.7.4 database on Solaris 8 (soon to be
upgraded to 10g)
Rule-based Optimizer
A query which has run for years using an indexed access to a very
large table (maybe 100 million rows)
suddenly decides to use a full-table scan, shutting down a critical
business process.
Then after several hours, it switches back to using the index.
All concerned claim that nothing changed before or after.
Needless to say the business users are nervous. They think maybe the
database grew beyond some limit.
Can anyone think of an explanation?
Thanks,
Dennis Williams
Hemant K Chitale
http://web.singnet.com.sg/~hkchital
and
http://hemantscribbles.blogspot.com
and
http://hemantoracledba.blogspot.com
"A 'No' uttered from the deepest conviction is better than a 'Yes'
merely uttered to please, or worse, to avoid trouble."
Mohandas Gandhi Quotes
: http://www.brainyquote.com/quotes/authors/m/mohandas_gandhi.html
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