Re: Where art thou pg_clog?

Casey Duncan wrote:
>
> On Feb 15, 2007, at 1:46 PM, Alvaro Herrera wrote:
>
> >Casey Duncan wrote:
> >>We have a production system with multiple identical database
> >>instances on the same hardware, with the same configuration, running
> >>databases with the exact same schema. They each have different data,
> >>but the database sizes and load patterns are almost exactly the same.
> >>
> >>We are running pg 8.1.5 (upgraded the day before 8.1.6 came out, oh
> >>well ;^) and since then we have noticed the following error on two of
> >>the servers:
> >>
> >>2007-02-15 00:35:03.324 PST ERROR: could not access status of
> >>transaction 2565134864
> >>2007-02-15 00:35:03.325 PST DETAIL: could not open file "pg_clog/
> >>098E": No such file or directory
> >
> >Can you relate it to autovacuum?
>
> Maybe. Here's what I get when I crank up the logging to debug4:
>
> 2007-02-15 14:20:48.771 PST DEBUG: StartTransaction
> 2007-02-15 14:20:48.771 PST DEBUG: name: unnamed; blockState:
> DEFAULT; state: INPROGR, xid/subid/cid: 3429052708/1/0, nestlvl: 1,
> children: <>
> 2007-02-15 14:20:48.771 PST DEBUG: vacuuming "pg_catalog.pg_statistic"
> 2007-02-15 14:20:48.771 PST ERROR: could not access status of
> transaction 2565134864
> 2007-02-15 14:20:48.772 PST DETAIL: could not open file "pg_clog/
> 098E": No such file or directory
> 2007-02-15 14:20:48.772 PST DEBUG: proc_exit(0)
> 2007-02-15 14:20:48.772 PST DEBUG: shmem_exit(0)
> 2007-02-15 14:20:48.773 PST DEBUG: exit(0)
> 2007-02-15 14:20:48.775 PST DEBUG: reaping dead processes
>
> does that imply that it is the pg_statistic table that is hosed?
>
> Interestingly I can manually vacuum that table in all of the
> databases on this machine without provoking the error.

Except template0 I presume? Is this autovacuum running in template0
perchance? I note that 800 million transactions have passed since the
Xid in the error message was current.

--
Alvaro Herrera http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.