Re: Creating Histograms

From: Tanel Põder <tanel.poder.003_at_mail.ee>
Date: Sat, 24 Jul 2004 14:29:47 +0300
Message-ID: <364801c47171$8a976fc0$0a879fd9@porgand>

> I think someone explained you may not always get same plan. One
> reason is CBO still looks at table HWM. But it's still worth doing.

CBO doesn't look at table's real HWM when optimizing a query, it uses the stats from the point in time when they were gathered. When stats (including system stats), optimizer parameters (including *_area_sizes) and real values in predicates stay constant, then the execution plan should stay the same for a given query, unless you encounter some bugs...

Tanel.

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Received on Sat Jul 24 2004 - 06:26:33 CDT