Обсуждение:

Hi All,<br /><br />I'm having very strange problems with indexing, I have a large number of partial indexes, when i try
torun some queries sometimes the queries run very fast and sometimes they are 100times slower than what i ran
before.....Itried running vacuum analyze couple of times and it dint help me at all. Also i tried the explain analyze
andwhat i found was the query execution plan keeps on changes. Is there any better way to gain control over these, I
triedturning seqscan off, and messing with some other parameters but dint really help. Also can somebody point me out
tolinks which explains more about query execution plans..i.e. each of parameters like bitmap heap scan, index
scan....etc...<br /><br />-- <br />Thanks,<br />Sumeet  

On Tue, Aug 29, 2006 at 12:44:28PM -0400, Sumeet wrote:
> me at all. Also i tried the explain analyze and what i found was the query
> execution plan keeps on changes. Is there any better way to gain control

My bet is that you don't have enough sample data to support a
consistent query plan.  SET STATISTICS might be what you need.

> parameters but dint really help. Also can somebody point me out to links
> which explains more about query execution plans..i.e. each of parameters
> like bitmap heap scan, index scan....etc...

On [mumble techdocs I think] there's a tutorial called EXPLAIN
explained.  Google will help you -- just use that title, with maybe
"postgresql" tacked onto your search string.

A

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Andrew Sullivan  | ajs@crankycanuck.ca
The plural of anecdote is not data.    --Roger Brinner