To: Mike Williams <mike.williams@comodo.com>
cc: pgsql-admin@postgresql.org
Subject: Re: ERROR: could not open segment 1 of relation 1663/743352/743420
	(target block 6407642): No such file or directory
In-reply-to: <201003281841.41865.mike.williams@comodo.com> 
References: <201003281841.41865.mike.williams@comodo.com>
Comments: In-reply-to Mike Williams <mike.williams@comodo.com>
	message dated "Sun, 28 Mar 2010 17:41:41 -0000"
Date: Sun, 28 Mar 2010 14:20:27 -0400
Message-ID: <25082.1269800427@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

Mike Williams <mike.williams@comodo.com> writes:
> We upgraded from 8.3.5 to 8.3.9 yesterday, after an extended period of 
> testing, to 8.3.10 today in hope of fixing it, and we're getting the following 
> error on occasion.

> ERROR:  could not open segment 1 of relation 1663/743352/743420 (target block 
> 2171336): No such file or directory
> CONTEXT:  SQL statement "SELECT day FROM min_stats WHERE day<= $1  AND 
> unique_ip=-1 ORDER BY day DESC LIMIT 1"
> PL/pgSQL function "update_unique_ips" line 13 at SQL statement

> update_unique_ips() is called once per minute, but we get anywhere from one 
> error per minute, to one error per hour.

> Relation 743420 in database 743352 is 441270272 bytes long and growing by a 
> few thousand bytes here and there.
> Obviously, as we've gone from 8.3.9 to 8.3.10, we're restarted postgres a few 
> times. We have also REINDEXd each table, the database, dropped and re-created 
> all the indexes.
> I've even pg_dump'd the database, and loaded it into a fresh database. The 
> relation numbers changed, but the 1663 bit remained the same.

Wow.  The symptom seems to be what you'd get from a corrupt tuple
pointer in an index, but it's hard to believe that such a thing would
persist over reindexes and even reloads.  Is the "target block" number
always the same, or does that change?  Can you reproduce the problem on
a different machine?  What platform are you running on?

			regards, tom lane