Re: Getting to 8.3 beta1

I wrote:
> Looking back at your original discussion of the bug,
> http://archives.postgresql.org/pgsql-hackers/2007-06/msg00234.php
> I'm wondering why you chose option #3 rather than option #4?
> I still find the proposed patch a bit crufty.

In particular, it seems like a patch per #4 would be a one-liner:

*** src/backend/access/transam/xlog.c.orig    Wed Sep 26 18:36:30 2007
--- src/backend/access/transam/xlog.c    Thu Sep 27 12:20:56 2007
***************
*** 5092,5101 ****      *      * If we stopped short of the end of WAL during recovery, then we are      * generating a
newtimeline and must assign it a unique new ID.      * Otherwise, we can just extend the timeline we were in when we
ranout      * of WAL.      */
 
!     if (needNewTimeLine)     {         ThisTimeLineID = findNewestTimeLine(recoveryTargetTLI) + 1;
ereport(LOG,
--- 5092,5103 ----      *      * If we stopped short of the end of WAL during recovery, then we are      * generating a
newtimeline and must assign it a unique new ID.
 
+      * We also force a new timeline when recovering from an archive, to avoid
+      * problems with trying to overwrite existing archived segments.      * Otherwise, we can just extend the
timelinewe were in when we ran out      * of WAL.      */
 
!     if (needNewTimeLine || (InArchiveRecovery && XLogArchivingActive()))     {         ThisTimeLineID =
findNewestTimeLine(recoveryTargetTLI)+ 1;         ereport(LOG,
 

though I admit I've not tested this.  The comments in
exitArchiveRecovery probably need adjustment too --- re-reading them,
it seems obvious that the current approach is broken by design, because
it *must* lead to an attempt to overwrite a previously archived version
of the last segment.
        regards, tom lane