Re: Serious problem: media recovery fails after system or PostgreSQL crash

From: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
> Well, that's unfortunate, but it's not clear that automatic recovery is
> possible. The only way out of it would be if an undamaged copy of the
> segment was in pg_xlog/ ... but if I recall the logic correctly, we'd
> not even be trying to fetch from the archive if we had a local copy.

No, PG will try to fetch the WAL file from pg_xlog when it cannot get it
from archive. XLogFileReadAnyTLI() does that. Also, PG manual contains the
following description:

http://www.postgresql.org/docs/9.1/static/continuous-archiving.html#BACKUP-ARCHIVING-WAL

WAL segments that cannot be found in the archive will be sought in pg_xlog/;
this allows use of recent un-archived segments. However, segments that are
available from the archive will be used in preference to files in pg_xlog/.

So, continuing recovery by changing the emode to LOG would work. What do
you think about this fix?

> I think having PG automatically destroy archive files is bordering on
> insane.

I agree. Before that, PG cannot know the archive location, so PG cannot
delete the partially filled archive files.

Regards
MauMau