Re: Another question on indexes (drop and recreate)

From: John A Meinel <john(at)arbash-meinel(dot)com>
To: Yves Vindevogel <yves(dot)vindevogel(at)implements(dot)be>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Another question on indexes (drop and recreate)
Date: 2005-06-21 15:49:28
Message-ID: 42B83708.2050706@arbash-meinel.com
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Yves Vindevogel wrote:

> And, after let's say a week, would that index still be optimal or
> would it be a good idea to drop it in the weekend and recreate it.

It depends a little bit on the postgres version you are using. If you
are only ever adding to the table, and you are not updating it or
deleting from it, I think the index is always optimal.
Once you start deleting from it there are a few cases where older
versions would not properly re-use the empty entries, requiring a
REINDEX. (Deleting low numbers and always adding high numbers was one of
the cases)

However, I believe that as long as you vacuum often enough, so that the
system knows where the unused entries are, you don't ever have to drop
and re-create the index.

John
=:->

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