Re: Command to prune archive at restartpoints

Committed.

Heikki Linnakangas wrote:
> One awkward omission in the new built-in standby mode, mainly used for
> streaming replication, is that there is no easy way to delete old
> archived files like you do with the %r parameter to restore_command.
> This was discussed at
> http://archives.postgresql.org/pgsql-hackers/2010-02/msg01003.php, among
> other things.
>
> Per discussion, attached patch adds a new restartpoint_command option to
> recovery.conf. That's an external shell command just like
> recovery_end_command that's executed at every restartpoint. You can use
> the %r parameter to pass the filename of the oldest WAL file that needs
> to be retained.
>
> While developing this I noticed that %r in recovery_end_command is not
> working correctly:
>
> LOG: redo done at 0/14000C10
> LOG: last completed transaction was at log time 2000-01-01
> 02:21:08.816445+02
> cp: cannot stat
> `/home/hlinnaka/pgsql.cvshead/walarchive/000000010000000000000014': No
> such file or directory
> cp: cannot stat
> `/home/hlinnaka/pgsql.cvshead/walarchive/00000002.history': No such file
> or directory
> LOG: selected new timeline ID: 2
> cp: cannot stat
> `/home/hlinnaka/pgsql.cvshead/walarchive/00000001.history': No such file
> or directory
> LOG: archive recovery complete
> LOG: checkpoint starting: end-of-recovery immediate wait
> LOG: checkpoint complete: wrote 0 buffers (0.0%); 0 transaction log
> file(s) added, 0 removed, 0 recycled; write=0.000 s, sync=0.000 s,
> total=0.003 s
> LOG: executing recovery_end_command "echo recovery_end_command %r"
> recovery_end_command 000000000000000000000000
> LOG: database system is ready to accept connections
> LOG: autovacuum launcher started
>
> Note how %r is always expanded to 000000000000000000000000. That's
> because %r is expanded only when InRedo is true, which makes sense for
> restore_command where that piece of code was copy-pasted from, but it's
> never true anymore when recovery_end_command is run. The attached patch
> fixes that too.
>
> Barring objections, I will commit this later today.
>
>

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com