On Thu, Oct 17, 2013 at 8:57 AM, Amit Kapila <amit.kapil...@gmail.com> wrote: > On Wed, Oct 16, 2013 at 4:30 AM, Gibheer <gibh...@zero-knowledge.org> wrote: >> On Mon, 14 Oct 2013 11:52:57 +0530 >> Amit Kapila <amit.kapil...@gmail.com> wrote: >> >>> On Sun, Oct 13, 2013 at 2:08 PM, Gibheer <gibh...@zero-knowledge.org> >>> wrote: >>> > On Sun, 13 Oct 2013 11:38:17 +0530 >>> > Amit Kapila <amit.kapil...@gmail.com> wrote: >>> > >>> >> On Thu, Oct 10, 2013 at 3:17 AM, Gibheer >>> >> <gibh...@zero-knowledge.org> wrote: >>> >> > On Mon, 7 Oct 2013 11:39:55 +0530 >>> >> > Amit Kapila <amit.kapil...@gmail.com> wrote: >>> >> >> Robert Haas wrote: >>> >> >> On Mon, Aug 5, 2013 at 2:04 AM, Andres Freund >>> >> >> <andres(at)2ndquadrant(dot)com> wrote: >> I would be glad, if you could also test the patch again, as I'm nearly >> code blind after testing it for 4 hours. >> I had the problem, that I could not attach as many replication >> connections as I wanted, as they were denied as normal connections. I >> think I got it fixed, but I'm not 100% sure at the moment. >> After some sleep, I will read the code again and test it again, to make >> sure, it really does what it is supposed to do. > > You have forgotten to attach the patch. However, now it is important > to first get the consensus on approach to do this feature, currently > there are 3 approaches: > 1. Have replication_reserved_connections as a separate parameter to > reserve connections for replication > 2. Consider max_wal_sender to reserve connections for replication > 3. Treat replication connections as a pool outside max_connections > > Apart from above approaches, we need to think how user can view the > usage of connections, as pg_stat_activity doesn't show replication > connections, so its difficult for user to see how the connections are > used. > > I am really not sure what is best way to goahead from here, but I > think it might be helpful if we can study some use cases or how other > databases solve this problem.
Today I spent some time seeing how other databases (in particular MySQL) achieve it. There seems to be no separate way to configure replication connections, rather if user faced with too_many_connections (https://dev.mysql.com/doc/refman/5.5/en/too-many-connections.html), they allow one spare connection (super user connection) to check what all connections are doing, it seems all connections can be viewed through one common command Show ProcessList (https://dev.mysql.com/doc/refman/5.5/en/show-processlist.html). By above, I don't mean that we should only do what other databases have done, rather it is towards trying to find a way which can be useful for users of Postgresql. Your views/thoughts? With Regards, Amit Kapila. EnterpriseDB: http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers