Re: Stefan's bug (was: max_standby_delay considered harmful)

On Mon, May 17, 2010 at 10:25 AM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> Therefore I think
> Fujii Masao's original idea was the best, but I have what I believe is
> an equivalent but simpler implementation, which is attached.

Seems good.

I found another two problems related to shutdown in PM_STARTUP state:

(1)
Smart or fast shutdown requested in PM_STARTUP state always removes
the backup_label file if it exists. But it might be still required
for subsequent recovery. I changed your patch so that additionally
the postmaster skips deleting the backup_label in that case.

(2)
pg_ctl -ms stop emits the following warning whenever there is the
backup_label file in $PGDATA.

WARNING: online backup mode is active
Shutdown will not complete until pg_stop_backup() is called.

This warning doesn't fit in with the shutdown during recovery case.
Since smart shutdown might be requested by other than pg_ctl, the
warning should be emitted in server side rather than client, I think.
How about moving the warning to the server side?

> Thoughts?  Should we try to fix this in 8.4 also, or just in HEAD?
> 8.3 and 8.2 never handle a smart shutdown prior to entering normal
> running, and while that seems pretty useless, doing something
> different would be a behavior change, so that seems like a
> non-starter.  8.4 has the same behavior as HEAD, though it's not
> documented in the release notes, so it's not clear how intentional the
> change was.

In 8.4, smart shutdown during recovery waits until the startup process
has exited. So the backporting to 8.4 doesn't improve any situation,
I think.

Regards,

--
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center