> On 24 Mar 2016, at 17:03, Robert Haas <robertmh...@gmail.com> wrote: > > On Wed, Mar 23, 2016 at 1:44 AM, Craig Ringer <cr...@2ndquadrant.com> wrote: >> On 10 March 2016 at 22:50, Stas Kelvich <s.kelv...@postgrespro.ru> wrote: >>> Hi. >>> >>> Here is proof-of-concept version of two phase commit support for logical >>> replication. >> >> I missed this when you posted it, so sorry for the late response. >> >> I've read through this but not tested it yet. I really appreciate you doing >> it, it's been on my wishlist/backburner for ages. >> >> On reading through the patch I noticed that there doesn't seem to be any >> consideration of locking. The prepared xact can still hold strong locks on >> catalogs. How's that handled? I think Robert's group locking stuff is what >> we'll want here - for a prepared xact we can join the prepared xact as a >> group lock member so we inherit its locks. Right now if you try DDL in a >> prepared xact I suspect it'll break. > > I have grave doubts about that approach. It's not impossible it could > be right, but I wouldn't bet the farm on it. >
I think all the locking already handled properly by creating dummy backend in PGPROC, as it done in usual postgres 2pc implementation. Just checked DDL with following scenario: * prepare tx that inserts a row in table on master * execute DROP TABLE on pglogical slave * commit prepared on master Now it behaves as expected — slave blocks DROP TABLE until commit prepared on master. --- Stas Kelvich Postgres Professional: http://www.postgrespro.com Russian Postgres Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
