Hi,
On 2014-09-01 10:25:58 +0200, Bernd Helmle wrote:
> --On 1. September 2014 17:00:32 +0900 Michael Paquier
> <michael.paquier@gmail.com> wrote:
>
> >Currently pg_dump does not allow a user to specify an exported snapshot
> >name that he would like to use for a dump using SET TRANSACTION SNAPSHOT
> >(now pg_export_snapshot is only used for parallel pg_dump within it). I
> >imagine that this would be handy to take a consistent dump of a given
> >database after creating a logical replication slot on it. Thoughts?
Yes, I always wanted that option.
> There was a discussion of this kind of feature some time ago here:
>
> <http://www.postgresql.org/message-id/CA+U5nMK9+TTCff_-4MfdxWHnASTAuHuq7u7uedD57vaY28AsQA@mail.gmail.com>
I was never convinced of the reasoning in that thread. Possibly things
have changed enough now that logical decoding is in core...
> Not sure if all the arguments holds still true with the appearance of MVCC
> catalog scans.
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.
Greetings,
Andres Freund
-- Andres Freund http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services