On Mon, 2011-01-10 at 17:05 +0200, Heikki Linnakangas wrote: > On 10.01.2011 16:49, Simon Riggs wrote: > > On Mon, 2011-01-10 at 15:20 +0100, Magnus Hagander wrote: > >> On Sun, Jan 9, 2011 at 15:53, Simon Riggs<si...@2ndquadrant.com> wrote: > >>> On Sun, 2011-01-09 at 12:52 +0100, Magnus Hagander wrote: > >>> > >>>> One thing I noticed is that it gives an interesting property to my > >>>> patch for streaming base backups - they now show up in > >>>> pg_stat_replication, with a streaming location of 0/0. > >>>> > >>>> If the view is named pg_stat_replication, we probably want to filter > >>>> that out somehow. But then, do we want a separate view listing the > >>>> walsenders that are busy sending base backups? > >>>> > >>>> For that matter, do we want an indication that separates a walsender > >>>> not sending data from one sending that happens to be at location 0/0? > >>>> Most will leave 0/0 really quickly, but a walsender can be idle (not > >>>> received a command yet), or it can be running IDENTIFY_SYSTEM for > >>>> example. > >>> > >>> I think we need a status enum. ('BACKUP', 'CATCHUP', 'STREAM') for the 3 > >>> phases of replication. > >> > >> That seems reasonable. But if we keep BACKUP in there, should we > >> really have it called pg_stat_replication? (yeah, I know, I'm not > >> giving up :P) > >> > >> (You'd need a 4th mode for WAITING or so, to indicate it's waiting for > >> a command) > > > > That's something different. > > > > The 3 phases are more concrete. > > > > BACKUP --> CATCHUP<---> STREAM > > > > When you connect you either do BACKUP or CATCHUP. Once in CATCHUP mode > > you never issue a BACKUP. Once we have caught up we move to STREAM. That > > has nothing to do with idle/active. > > So how does a walsender that's waiting for a command from the client > show up? Surely it's not in "catchup" mode yet?
There is a trivial state between connect and first command. If you think that is worth publishing, feel free. STARTING? -- 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