On Tue, Sep 16, 2014 at 2:19 PM, Michael Paquier <michael.paqu...@gmail.com> wrote: > On Tue, Sep 16, 2014 at 5:25 AM, Robert Haas <robertmh...@gmail.com> wrote: >> On Mon, Sep 15, 2014 at 3:00 PM, Michael Paquier >> <michael.paqu...@gmail.com> wrote: >>> At least a set of hooks has the merit to say: do what you like with >>> your synchronous node policy. >> >> Sure. I dunno if people will find that terribly user-friendly, so we >> might not want that to be the ONLY thing we offer. > Well, user-friendly interface is actually the reason why a simple GUC > integer was used in the first series of patches present on this thread > to set as sync the N-nodes with the lowest priority. I could not come > up with something more simple. Hence what about doing the following: > - A patch refactoring code for pg_stat_get_wal_senders and > SyncRepReleaseWaiters as there is in either case duplicated code in > this area to select the synchronous node as the one connected with > lowest priority
A strong +1 for this idea. I have never liked that, and cleaning it up seems eminently sensible. > - A patch defining the hooks necessary, I suspect that two of them are > necessary as mentioned upthread. > - A patch for a contrib module implementing an example of simple > policy. It can be a fancy thing with a custom language or even a more > simple thing. I'm less convinced about this part. There's a big usability gap between a GUC and a hook, and I think Heikki's comments upthread were meant to suggest that even in GUC-land we can probably satisfy more use cases that what this patch does now. I think that's right. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
