Re: BUG #6167: pg_dump fails on table lock

On Thu, Aug 18, 2011 at 2:05 AM, Jesper Engman <jesper(at)engman(dot)net> wrote:
>
> The following bug has been logged online:
>
> Bug reference:      6167
> Logged by:          Jesper Engman
> Email address:      jesper(at)engman(dot)net
> PostgreSQL version: 8.3.10
> Operating system:   Linux
> Description:        pg_dump fails on table lock
> Details:
>
> I have tables that exists for short time periods, sometimes for as short as
> 5 min. pg_dump is starting to fail due to a problem to lock these tables:
>
> pg_dump: SQL command failed
> pg_dump: Error message from server: ERROR: relation
> "vehicle_change_partitions.vehicle_change_export_p4368494" does not exist
> pg_dump: The command was: LOCK TABLE
> vehicle_change_partitions.vehicle_change_export_p4368494 IN ACCESS SHARE
> MODE
> Backup failed: PGPASSWORD=xxxxx && export PGPASSWORD && export PGOPTIONS="-c
> statement_timeout=0 -c maintenance_work_mem=2147483647" && /usr/bin/pg_dump
> -h xxx.xxx.xxx.xxx -U postgres --ignore-version -Fc -Z 6 xxxxxxxx >
> /vol/nfs_backup/postgres_dumps/2011_07_13/xxxxxxxx_2011_07_13
> Account: xxxxxxxx Backup failed
>
> How is this possible - pg_dump is a serializable transaction? It doesn't
> seem to be tripped up by some other backend function since this actually
> fails on the lock.

Well, its not a bug.

You've asked to dump a table and then dropped the table concurrently
with the attempt to dump the table.

Exclude the tables you don't wish to have dumped using command line options.

I don't think we will put in an option to silently exclude missing
tables, not least because it would be technically difficult.

--
 Simon Riggs                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services