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Message Posted: Wed, 06 Sep 2006 @ 09:54:31 GMT

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Hello,

Dieter wrote:

First, I've always considered Soft RI as a kind of hint to the optimizer.

More generally, I submitted the follwing ER to PAC last year:

ER Subject (Short Description):

Ability of the optimizer to "take more time to optimize"

Enhancement Description:

In general the optimizer needs to come up with a good plan quickly. Therefore it needs to be conservative in general.

This could hurt, and I belive it does hurt, long-running queries that needs "the best plan". For example building a large summery table, or the equivalent creation of an aggregate join index. For such queries I think it would be benificial, if the optimizer did take it's time to try to be more aggressive (or more thorough) in the estimation of different plan options.

This feature could be an option on a query, and/or a session-parameter.

The ER was rejected, because it is "not in line with product direction".

What I was trying to adress was the dilemma the optimizer faces:

Fast generated good plans for tactical queries versus not so fast generated optimal plans for long running queries.

Ole Dunweber
Coop Nordic

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