| From: | Jérôme BENOIS <benois(at)argia-engineering(dot)fr> |
|---|---|
| To: | db(at)zigo(dot)dhs(dot)org |
| Cc: | PostgreSQL Performance <pgsql-performance(at)postgresql(dot)org>, Xavier Milliard <milliard(at)argia(dot)fr>, Laurent BELMONTE <belmonte(at)argia(dot)fr> |
| Subject: | Re: BitMapScan performance degradation |
| Date: | 2006-11-21 15:35:56 |
| Message-ID: | 1164123356.5281.256.camel@localhost.localdomain |
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| Lists: | pgsql-performance |
Hi Dennis,
Le mardi 21 novembre 2006 à 16:12 +0100, db(at)zigo(dot)dhs(dot)org a écrit :
> > When enable_bitmapscan is enabled this query cost 51893.491 ms and when
> > is disabled 117.709 ms. But i heard bitmapscan feature improved
> > performance, can you help me ?
>
> The standard question we always ask first is if you have run VACUUM
> ANALYZE recently?
Yes i ran VACCUUM ANALYZE just before my EXPLAIN.
> Are all the costs and estimated number of rows the same after you have run
> VACUUM ANALYZE? If not you might want to show that new plan as well.
>
> /Dennis
Jérôme.
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