El 22/12/17 a las 18:53, Jeremy Finzel escribió: > I am attempting to build several indexes in parallel, guaranteeing that > I never build one on the same table twice. I understand I can't build > two on the same table at once or I will get a deadlock. However, I am > also getting a deadlock when doing several in parallel on different tables. On the same table you wouldn't get a dead lock as CREATE INDEX CONCURRENTLY takes a "share update exclusive lock" which is incompatible with vacuum and schema changes (and stronger locks), and a second CREATE INDEX CONCURRENTLY would be another schema change. So the first one would lock the second, which will have to wait until completion of the locking statement. > Here is an example of the error I am getting: > > 2017-12-22 15:48:07.669 CST,"CREATE INDEX",2017-12-22 15:48:02 > CST,8/32,0,ERROR,40P01,"deadlock detected","Process 4470 waits for > ShareLock on virtual transaction 4/262; blocked by process 4466. > Process 4466 waits for ShareLock on virtual transaction 8/32; blocked by > process 4470. > Process 4470: CREATE INDEX CONCURRENTLY index_foo_on_created_at ON foo > USING btree (created_at); > Process 4466: CREATE INDEX CONCURRENTLY index_bar_on_id ON bar USING > btree (id);","See server log for query details.",,,,"CREATE INDEX > CONCURRENTLY index_foo_on_created_at ON foo USING btree (created_at);",,,"" The only thing I can think of is that there's a foreign key from foo to bar(id), but the create index on bar shouldn't prevent a share lock on foo, even if such a restriction exists. -- Martín Marqués http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
