Re: could not access status of transaction 0 - Mailing list pgsql-hackers

From Tom Lane
Subject Re: could not access status of transaction 0
Date
Msg-id 13511.1137822164@sss.pgh.pa.us
Whole thread Raw
In response to could not access status of transaction 0  (Stefan Kaltenbrunner <stefan@kaltenbrunner.cc>)
List pgsql-hackers
Stefan Kaltenbrunner <stefan@kaltenbrunner.cc> writes:
> We seem to be getting this error (in german) once in a while on a rather
> complex database:

> FEHLER:  konnte auf den Status von Transaktion 0 nicht zugreifen
> DETAIL:  kann Datei >>/var/databases/postgres/data/pg_subtrans/57DA<<
> nicht erstellen: Die Datei existiert bereits

> which roughly translates to

> ERROR: could not access status of transaction 0
> DETAIL: could not create file
> /var/databases/postgres/data/pg_subtrans/57DA<<: File exists

I think we've finally identified the reason for this:
http://archives.postgresql.org/pgsql-committers/2006-01/msg00287.php

> It might be interesting to note that we use slony to replicate a few
> tables of this database to multiple slaves and according to our logs it
> always was the slony-user connected to the database that triggered this
> error.

AFAICT Slony is blameless; the triggering condition is a very high
transaction rate (2000 or more transactions between checkpoints)
plus the bad luck to hit a fairly narrow race-condition window.
        regards, tom lane


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