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RE: Long execute phase for SELECT query

From: ramick <>
Date: Fri, 30 Jun 2006 09:37:43 -0700
Message-Id: <>

Both of these parameters seem to be session modifiable - you could set one or both in just those sessions with SQL that have a large number of tables producing the large number of permutations...

-----Original Message-----

From: [] Sent: Thursday, June 29, 2006 1:15 PM
To: Michael McMullen; Subject: RE: Long execute phase for SELECT query

Oops - I just realized I misread your email - I thought it said optimizer_features_enable. Optimizer_max_permutations is hidden in 10g and defaults to 2000. I just tried setting it to 1000, and sure enough it cut the parse time in half - down to 6 seconds from 12 seconds, but still much longer than it was taking in 8.0.6 with the same setting (1000) for opmtizer_max_permutations. Next I tested with o_m_p=100 and that brought the parse time down to a respectable .95 seconds, but I don't think I want to go with that low of a setting instance wide though. I'd imagine it could have some nasty side effects.

I also tested with _b_tree_bitmap_plans=FALSE and that cut the parse time down from 12 to 6 as well, but that's another one I'm not so sure I want to set instance wide.

-----Original Message-----

From: Michael McMullen [] Sent: Thursday, June 29, 2006 12:00 PM
To: Allen, Brandon; Subject: Re: Long execute phase for SELECT query

optimizer_max_permutations still be set in 10g? If so, you could try playing with that.

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-- Received on Fri Jun 30 2006 - 11:37:43 CDT

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