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From: Scott Marlowe <smarlowe@g2switchworks.com>
To: Carlo Stonebanks <stonec.register@sympatico.ca>
Cc: pgsql-performance@postgresql.org
Subject: Re: Performance Optimization for Dummies 2 - the SQL
Date: Fri, 06 Oct 2006 11:53:43 -0500
Message-ID: <1160153623.6181.13.camel@state.g2switchworks.com> (raw)
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On Fri, 2006-10-06 at 11:44, Carlo Stonebanks wrote:
> This didn't work right away, but DID work after running a VACUUM FULL. In 
> other words, i was still stuck with a sequential scan until after the 
> vacuum.
> 
> I turned autovacuum off in order to help with the import, but was perfoming 
> an ANALYZE with every 500 rows imported.
> 
> With autovacuum off for imports, how frequently should I VACUUM?

Basically once the query planner stops using seq scans is usually good
enough, although sometimes there's a bit of a period where it'll be
using nested loops and then switch to merge etc...

Every 500 is probably a bit much.  After the first few thousand rows,
run an analyze, and after about 5 to 10 thousand another analyze and you
should be set.



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