Re: select count(*) very slow on an already vacuumed table.

Richard Huxton wrote:

>On Wednesday 14 April 2004 18:53, Rajesh Kumar Mallah wrote:
>
>
>>Hi
>>I have .5 million rows in a table. My problem is select count(*) takes
>>ages. VACUUM FULL does not help. can anyone please tell me
>>how to i enhance the performance of the setup.
>>
>>
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>
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>>SELECT count(*) from eyp_rfi;
>>
>>
>
>If this is the actual query you're running, and you need a guaranteed accurate
>result, then you only have one option: write a trigger function to update a
>table_count table with every insert/delete to eyp_rfi.
>
>

it is just an example. in general all the queries that involves eyp_rfi
become slow. reloading the table makes the query faster.

mallah.

>There is loads of info on this (and why it isn't as simple as you might think)
>in the archives. First though:
>1. Is this the actual query, or just a representation?
>2. Do you need an accurate figure or just something "near enough"?
>
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>