Re: The last WAL segment of the old timeline is not archived for a while after archive recovery

From: Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
To: Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
Cc: pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: The last WAL segment of the old timeline is not archived for a while after archive recovery
Date: 2009-04-22 19:51:17
Message-ID: 49EF7535.40006@enterprisedb.com
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Fujii Masao wrote:
> In archive recovery, the last applied WAL segment may not have
> .ready file in spite of not having been archived yet. Then, this
> segment is not archived until a future checkpoint creates .ready
> file. It's a little dangerous that there is the WAL segment which
> is not archived for a while.
>
> Attached patch fixes this problem. Is this worth committing?

Yeah, I think it is. Applied.

BTW, I notice that we have the same problem with WAL files that have
been manually copied into pg_xlog, in the unlikely corner case that the
"backup redo point", ControlData->checkpointCopy, points to the
first-ever WAL file. That's because we then skip the
RemoveOldXlogFiles() step in the startup checkpoint, which normally
creates the .ready files for all but the last WAL file. I don't think
that happens in practice, and if it does, the files will still be
archived at the next checkpoint, so I think we can leave it as it is.

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

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