On 02/05/17 04:14, Peter Eisentraut wrote: > On 4/30/17 20:31, Andres Freund wrote: >> On 2017-04-26 23:41:51 +0200, Petr Jelinek wrote: >>> Yes that's result of how logical replication slots work, the transaction >>> that needs to finish is your transaction. It can be worked around by >>> creating the slot manually via the SQL interface for example and create >>> the subscription using WITH (NOCREATE SLOT, SLOT NAME = 'your slot') . >> >> Is there any chance the creation of the slot could be moved ahead, to >> before an xid has been assigned? > > The trend has rather been to do most of the stuff before creating the > slot, so that all the error checking is done. See for example > dcb39c37c1d3b90115e1501af8efb7af59c341c3. >
Yes because otherwise we risk leaving slot on the upstream if the command fails downstream. We could move the slot creation outside of tx as I proposed, then we risk leaving subscription downstream without slot upstream though but I think that's less of a issues from user friendliness and mainly safety (slot reserves wal and global catalog xmin while subscription does not reserve anything except the name of the subscription). -- 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
