Re: tsearch query plan

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От Josh Berkus
Тема Re: tsearch query plan
Дата
Msg-id 200404081633.40388.josh@agliodbs.com
обсуждение исходный текст
Ответ на tsearch query plan  (Mark Lubratt <mark.lubratt@indeq.com>)
Ответы Re: tsearch query plan  (Mark Lubratt <mark.lubratt@indeq.com>)
Список pgsql-performance
Mark,

> I've got one question about query planning.  Is it understandable to
> have the query plan estimation be off by a couple of orders of
> magnitude?  Or, is it the fact that the cost estimation is small to
> begin with that the error between the actual and the estimated is
> "normal"?

Well, your example is not "a couple orders of magnitude".   6 vs. 32 is
actually pretty good accuracy.

Now, 6 vs 192 would potentially be a problem, let alone 32 vs 13,471.

--
-Josh Berkus
 Aglio Database Solutions
 San Francisco


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