On Wed, May 3, 2017 at 4:18 PM, Michael Banck <michael.ba...@credativ.de> wrote:
> Hi, > > On Tue, May 02, 2017 at 11:13:58AM +0200, Magnus Hagander wrote: > > Looks good to me as well. Applied, with only a minor further docs > addition > > saying that this is the default also on the high availability page. > > I understand this is late, but a colleague alerted me to the following > behaviour change: If you recover a server with default settings, it is > our understanding that pg_isready will now return true immediately after > the consistent state is reached and possibly well before recovery had > actually ended (depending on the amount of outstanding wal). As hot > standby works with log shipping, this is independent of the > recovery.conf settings, i.e. even if standby_mode and primary_conninfo > are not set. So if one was monitoring recovery like that before and > expects pg_isready to only return true once the recovery is fully > complete, this will now have to be adjusted. Also, if the recovered > server is to be used for transactions, there will now be a window where > the server accepts connections, but is in read-only mode. > > Before, one had the make the concious choice to set hot_standby to get > the behaviour, now it might be surprising to users, or maybe I'm > overthinking this? > > If that is indeed the case, maybe it should be mentioned more > prominently in the documentation and/or get highlighted in the release > notes? > Hmm. That's an interesting usecase. I don't think it's a big enough one to revert this change, but it definitely makes sense to mention it under incompatible changes. I wonder if what we really want here, at least long-term, is a flag for pg_isready that makes it wait for a server to actually go out of recovery?`Seems that a tool like the one mentioned here would have to do that -- it can be done now by doing pg_isready first and then psql to check the status, but it seems like it could be a worthwhile addition? -- Magnus Hagander Me: https://www.hagander.net/ <http://www.hagander.net/> Work: https://www.redpill-linpro.com/ <http://www.redpill-linpro.com/>