On Fri, Jul 21, 2017 at 11:10:52PM +0800, Craig Ringer wrote: > What practical use cases are there for acting post-auth but that can't wait > until the user tries to do something?
Creating TEMP schema that triggers and functions might need. Doing CREATE TEMP TABLE IF NOT EXISTS in triggers slows things down. It'd be super nice if PostgreSQL had some sort of persistent TEMP schema option, where you can have schema elements that are persistent in that they're always there, but where the data is all TEMP. Oracle has this and they call it GLOBAL TEMP IIRC. There would be some caveats, such as not being able to have FKs between these sorts of persistent temp tables and persistent tables. In the absence of such a feature, a session hook/trigger is a great workaround. > Can a user do anything remotely interesting or useful without hitting > either ExecutorStart_hook or ProcessUtility_hook? They can parse queries I > guess but you could just set your hook up in the parser instead. If you > hook the parser all they can do is open an idle session and sit there... In any other hook you'd have to check whether the session setup work you wanted to do has been done. That could be potentially slow. I actually have an all SQL implementation of session/begin/commit triggers. The session triggers in that implementation only run on the first DML statement, which could be too late for OP's purpose. Nico -- -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers