On Mon, 2010-12-27 at 14:39 +0100, Magnus Hagander wrote: > On Thu, Dec 23, 2010 at 13:09, Magnus Hagander <mag...@hagander.net> wrote: > > This patch adds counters and views to monitor hot standby generated > > recovery conflicts. It extends the pg_stat_database view with one > > column with the total number of conflicts, and also creates a new view > > pg_stat_database_conflicts that contains a breakdown of exactly what > > caused the conflicts. > > > > Documentation still pending, but comments meanwhile is of course > > appreciated ;) > > Heikki pointed out over IM that it's pointless to count stats caused > by recovery conflict with drop database - since we drop the stats > record as soon as it arrives anyway. Here's an updated patch that > removes that, and also adds some documentation.
I like the patch, well inspired, code in the right places AFAICS. No code comments at all. Couple of thoughts: * are we safe to issue stats immediately before issuing FATAL? Won't some of them get lost? * Not clear what I'd do with database level information, except worry a lot. Maybe an option to count conflicts per user would be better, since at least we'd know exactly who was affected by those. Just an idea. * Would it better to have a log_standby_conflicts that allowed the opportunity to log the conflicting SQL, duration until cancelation etc? I'd rather have what you have than nothing at all though... the new hot_standby_feedback mode should be acting to reduce these, so it would be useful to have this patch enabled for testing that feature. -- Simon Riggs http://www.2ndQuadrant.com/books/ PostgreSQL Development, 24x7 Support, Training and Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers