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Re: count(*) slow on large tables

From: Shridhar Daithankar <shridhar_daithankar(at)persistent(dot)co(dot)in>
To: Dror Matalon <dror(at)zapatec(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: count(*) slow on large tables
Date: 2003-10-03 06:29:02
Message-ID: 3F7D172E.3060107@persistent.co.in (view raw or flat)
Thread:
Lists: pgsql-hackerspgsql-performance
Dror Matalon wrote:

> I smell a religious war in the aii:-). 
> Can you go several days in a row without doing select count(*) on any
> of your tables? 
> 
> I suspect that this is somewhat a domain specific issue. In some areas
> you don't need to know the total number of rows in your tables, in
> others you do. 

If I were you, I would have an autovacuum daemon running and rather than doing 
select count(*), I would look at stats generated by vacuums. They give 
approximate number of tuples and it should be good enough it is accurate within 
a percent.

Just another approach of achieving same thing.. Don't be religious about running 
a qeury from SQL prompt. That's it..

  Shridhar


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