On Thu, Jul 13, 2017 at 7:23 PM, Jeff Janes <jeff.janes@xxxxxxxxx> wrote: > On Thu, Jul 13, 2017 at 1:15 AM, Michael Paquier <michael.paquier@xxxxxxxxx> > wrote: >> >> On Thu, Jul 13, 2017 at 5:26 AM, Jeff Janes <jeff.janes@xxxxxxxxx> wrote: >> > >> > I think that none of the recovery information functions >> > >> > (https://www.postgresql.org/docs/9.6/static/functions-admin.html#FUNCTIONS-RECOVERY-INFO-TABLE) >> > can distinguish a hot standby which is connected to an idle master, >> > versus >> > one which is disconnected. For example, because the master has crashed, >> > or >> > someone has changed the firewall rules. >> > >> > Is there a way to monitor from SQL the last time the standby was able to >> > contact the master and initiate streaming with it? Other than trying to >> > write a function that parses it out of pg_log? >> >> Not directly I am afraid. One way I can think about is to poll >> periodically the state of pg_stat_replication on the primary or >> pg_stat_wal_receiver on the standby and save it in a custom table. The >> past information is not persistent as any replication-related data in >> catalogs is based on the shared memory state of the WAL senders and >> the WAL receiver, and those are wiped out at reconnection. > > > Thanks, that looks like what I want (or will be, once I get the other side > to upgrade to 9.6). > > I think that pg_stat_wal_receiver should be crossreferenced in > https://www.postgresql.org/docs/9.6/static/hot-standby.html, near the same > place which it crossreferences table 9-79. That would make it more > discoverable. Hm. Hot standby may not involve streaming replication. What about a paragraph here instead? https://www.postgresql.org/docs/devel/static/warm-standby.html#streaming-replication In the monitoring subsection, we could tell that on a standby the WAL receiver status can be retrieved from this view when changes are streamed. What do you think? -- Michael -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
