On Mon, 2006-08-07 at 13:05 -0400, Tom Lane wrote:
> Simon Riggs <[EMAIL PROTECTED]> writes:
> > I've implemented this for BTree, GIN, GIST using an additional rmgr
> > function    bool rm_safe_restartpoint(void)
> > ...
> > "Recovery checkpoints" are now renamed "restartpoints" to avoid
> > confusion with checkpoints. So checkpoints occur during normal
> > processing (only) and restartpoints occur during recovery (only).
> Applied with revisions.  

err....CheckPointGuts() :-)  I guess patch reviews need some spicing up.

> As submitted the patch pushed backup_label out
> of the way immediately upon reading it, which is no good: you need to be
> sure that the starting checkpoint location is written to pg_control
> first, else an immediate crash would allow the thing to try to start
> from whatever checkpoint is listed in the backed-up pg_control.  Also,
> the minimum recovery stopping point that's obtained using the label file
> still has to be enforced if there's a crash during the replay sequence.
> I felt the best way to do that was to copy the minimum stopping point
> into pg_control, so that's what the code does now.

Thanks for checking that.

> Also, as I mentioned earlier, I think that doing restartpoints on the
> basis of elapsed time is simpler and more useful than having an explicit
> distinction between "normal" and "standby" modes.  We can always invent
> a standby_mode flag later if we need one, but we don't need it for this.

OK, agreed.

The original thinking was that writing a restartpoint was more crucial
when in standby mode; but this way we've better performance and have a
low ceiling on the restart time if that should ever occur at the worst

Thanks again to Marko for the concept.

I'll work on the docs for backup.sgml also.

  Simon Riggs
  EnterpriseDB          http://www.enterprisedb.com

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