To: "TJ O'Donnell" <tjo@acm.org>
cc: pgsql-sql@postgresql.org
Subject: Re: ERROR: could not write block 196261 of temporary file: No space
	left
In-reply-to: <4511BA00.6070001@acm.org> 
References: <4511BA00.6070001@acm.org>
Comments: In-reply-to "TJ O'Donnell" <tjo@acm.org>
	message dated "Wed, 20 Sep 2006 15:00:32 -0700"
Date: Wed, 20 Sep 2006 18:31:46 -0400
Message-ID: <20066.1158791506@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

"TJ O'Donnell" <tjo@acm.org> writes:
> ERROR:  could not write block 196261 of temporary file: No space left
> on device

> I can't tell if this was because I ran out of real disk space,
> or because of some disk space limit set in pg config files.

There is no "disk space limit in pg config files".  Depending on your
platform, that error could represent a per-user disk quota limit being
enforced against the postmaster rather than genuine disk-full, but
whatever the limit was it's at the OS level not Postgres.

> I also can't tell if the error came from the Copy or the Insert.

Since it says "temporary file", it's not talking about insertion of data
into a real table (even a temporary one).  It's talking about genuinely
temporary intra-query workspace.  I'd venture that the error comes from
the SELECT DISTINCT step trying to write a sort temp file that there's
not room for.  (The fact that you see UPDATE 0 right after that is
further evidence for this theory --- after the failure, there's nothing
in fragment_table, so the UPDATE just falls through.)

			regards, tom lane