Re: Unarchived WALs deleted after crash

On 15.02.2013 17:12, Simon Riggs wrote:
> On 15 February 2013 14:31, Heikki Linnakangas<hlinnakangas@vmware.com>  wrote:
>>> -  /*
>>> -   * Normally we don't delete old XLOG files during recovery to
>>> -   * avoid accidentally deleting a file that looks stale due to a
>>> -   * bug or hardware issue, but in fact contains important data.
>>> -   * During streaming recovery, however, we will eventually fill the
>>> -   * disk if we never clean up, so we have to. That's not an issue
>>> -   * with file-based archive recovery because in that case we
>>> -   * restore one XLOG file at a time, on-demand, and with a
>>> -   * different filename that can't be confused with regular XLOG
>>> -   * files.
>>> -   */
>>> -   if (WalRcvInProgress() || XLogArchiveCheckDone(xlde->d_name))
>>> +   if (RecoveryInProgress() || XLogArchiveCheckDone(xlde->d_name))
>>>           [ delete the file ]
>>
>> With that commit, we started to keep WAL segments restored from the archive
>> in pg_xlog, so we needed to start deleting old segments during archive
>> recovery, even when streaming replication was not active. But the above
>> change was to broad; we started to delete old segments also during crash
>> recovery.
>>
>> The above should check InArchiveRecovery, ie. only delete old files when in
>> archive recovery, not when in crash recovery. But there's one little
>> complication: InArchiveRecovery is currently only valid in the startup
>> process, so we'll need to also share it in shared memory, so that the
>> checkpointer process can access it.
>>
>> I propose the attached patch to fix it.
>
> Agree with your diagnosis and fix.

Ok, committed. For the sake of the archives, attached is a script based
on Jehan-Guillaume's description that I used for testing (incidentally
based on Kyotaro's script to reproduce an unrelated problem in another
thread).

Thanks for the report!

- Heikki