Bryn Llewellyn <bryn@xxxxxxxxxxxx> writes: > I've seen this pattern in use: > create temp table if not exists pg_temp.flag(val boolean not null) on commit delete rows; > insert into pg_temp.flag(val) values(true); > But doing a DDL before every use of the session-state representation felt heavier than assuming that it's there and creating the table only if it isn't. But I haven't done any timing tests. Is the "create… if not exists" so lightweight when the to-be-created object does exist that I'm fussing over nothing? Fair question. My gut feeling is that the subtransaction created by the BEGIN ... EXCEPTION construct is more expensive than a no-op CREATE IF NOT EXISTS. I've not measured it though; and I'm pretty sure that the answer would vary depending on how often you expect the code to fall through versus needing to create the table. regards, tom lane
