Re: Names of run-time configuration parameters (was: Limiting the operations that client-side code can perform upon its database backend's artifacts)

Bryn Llewellyn <bryn(at)yugabyte(dot)com> 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