On Mon, Sep 1, 2014 at 5:30 AM, Andres Freund <and...@2ndquadrant.com> wrote: > Hi, > >> >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.
I didn't find that option to be terribly important then, but I don't see how we can possibly get by without it now, unless our goal is to make logical decoding as hard to use as we possibly can. Tom's got a good point about the order of locking vs. snapshot taking, but I think the way to address that is by adding some capability to temporarily lock out all DDL on non-temporary objects across the entire system, rather than by trying to make pg_dump (or the walsender creating the replication slot) lock every table. Even if we could get that to work, it still leaves the very-much-related problem that dumps of databases containing many tables can easily exhaust the lock table. -- 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
