On 07/02/17 01:00, Michael Paquier wrote: > On Tue, Feb 7, 2017 at 2:07 AM, Petr Jelinek > <petr.jeli...@2ndquadrant.com> wrote: >> On 06/02/17 05:15, Michael Paquier wrote: >>> Hi all, >>> >>> Lately I have bumped into a case where it would have been useful to >>> make the difference between a failure because of a slot already >>> dropped and an internal failure of Postgres. Is there any interest for >>> support of IE and INE for CREATE and DROP_REPLICATION_SLOT? >>> My use case involved only the SQL-callable interface, but I would >>> think that it is useful to make this difference as well with the >>> replication protocol. For the function we could just add a boolean >>> argument to control the switch, and for the replication commands a >>> dedicated keyword. >>> >>> Any thoughts? >> >> My thought is, how would this handle the snapshot creation that logical >> slot does when it's created? > > In what is that related to IF NOT EXISTS? If the slot does not get > created you could just return NULL to the caller to let him know that > there is something already around.
Well, the current behavior and the common use-case for creating logical slot via walsender is to get the snapshot which corresponds to LSN, the above would break that behavior for some variants of the command which I find rather confusing from user perspective. > The use-case I have found INE > useful involved physical slots actually. I am sure others would find it useful for logical ones as well. -- Petr Jelinek http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
