On 2014-09-01 21:54:24 +0900, Michael Paquier wrote: > On Mon, Sep 1, 2014 at 6:30 PM, Andres Freund <and...@2ndquadrant.com> wrote: > > I was never convinced of the reasoning in that thread. Possibly things > > have changed enough now that logical decoding is in core... > > Well, the test case I got in mind is only for taking a dump using the > latest state of a replication slot and not the snapshot export itself.
I don't think what you're proposing is really possible. Could you describe it in a bit more detail? > So what about the following: we let the user specify a slot name with > pg_dump, and take a dump using the latest snapshot that this > replication slot has reported to a user. There exists no snapshot sufficient for user data after slot creation. > > I don't think they change anything here. The problem is the, pretty > > fundamental, problem that you need to know a relation exists before > > executing a LOCK ...; on it. During that time somebody can change the > > schema. > > Doesn't this window exist as well with parallel pg_dump? Yes. I didn't say those reasons were convincing. The window is quite a bit smaller though. With the exported snapshot from CREATE REPLICATION SLOT it could convinceably be hours. Greetings, Andres Freund -- Andres Freund 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