Subject: Re: slow query
From: Robert Treat <xzilla@users.sourceforge.net>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Josh Berkus <josh@agliodbs.com>, Clarence Gardner <clarence@silcom.com>,
	Oleg Lebedev <oleg.lebedev@waterford.org>,
	"pgsql-performance@postgresql.org" <pgsql-performance@postgresql.org>
In-Reply-To: <5421.1046119835@sss.pgh.pa.us>
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Date: 25 Feb 2003 10:28:02 -0500
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On Mon, 2003-02-24 at 15:50, Tom Lane wrote:
> You'll
> particularly get burnt by indexes that are on OIDs or sequentially
> assigned ID numbers, since the set of IDs in use just naturally tends to
> migrate higher over time.  I don't think that the update rate per se has
> much to do with this, it's the insertion of new IDs and deletion of old
> ones that causes the statistical shift.  

Would it be safe to say that tables with high update rates where the
updates do not change the indexed value would not suffer from index
bloat? For example updates to non-index columns or updates that
overwrite, but don't change the value of indexed columns; do these even
need to touch the index? 

Robert Treat