Re: PITR potentially broken in 9.2

On 28.11.2012 06:27, Noah Misch wrote:
> On Tue, Nov 27, 2012 at 10:08:12AM -0800, Jeff Janes wrote:
>> Doing PITR in 9.2.1, the system claims that it reached a consistent
>> recovery state immediately after redo starts.
>> This leads to it various mysterious failures, when it should instead
>> throw a "requested recovery stop point is before consistent recovery
>> point" error.
>> (If you are unlucky, I think it might even silently start up in a
>> corrupt state.)
>
> I observed a similar problem with 9.2.  Despite a restore_command that failed
> every time, startup from a hot backup completed.  At the time, I suspected a
> mistake on my part.

I believe this was caused by this little typo/thinko:

> --- a/src/backend/access/transam/xlog.c
> +++ b/src/backend/access/transam/xlog.c
> @@ -6763,7 +6763,7 @@ StartupXLOG(void)
>                  /* Pop the error context stack */
>                  error_context_stack = errcontext.previous;
>
> -                if (!XLogRecPtrIsInvalid(ControlFile->backupStartPoint) &&
> +                if (!XLogRecPtrIsInvalid(ControlFile->backupEndPoint) &&
>                      XLByteLE(ControlFile->backupEndPoint, EndRecPtr))
>                  {
>                      /*

Normally, backupEndPoint is invalid, and we rely on seeing an
end-of-backup WAL record to mark the location. backupEndPoint is only
set when restoring from a backup that was taken from a standby, but
thanks to the above, recovery incorrectly treats that as end-of-backup.

Fixed, thanks for the report!

- Heikki