am Fri, dem 10.08.2007, um 17:46:11 +0800 mailte carter ck folgendes:
> Hi all,
>
> I am facing a performance issue here. Whenever I do a count(*) on a table
> that contains about 300K records, it takes few minutes to complete. Whereas
> my other application which is counting > 500K records just take less than
> 10 seconds to complete.
>
> I have indexed all the essential columns and still it does not improve the
> speed.
Indexes don't help in this case, a 'select count(*)' forces a seq. scan.
Do you realy need this information? An estimate for the number of rows
can you find in the system catalog (reltuples in pg_class, see
http://www.postgresql.org/docs/current/interactive/catalog-pg-class.html)
Andreas
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Andreas Kretschmer
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