On 2018-Oct-01, Peter Eisentraut wrote: > The following appears to work: > > CREATE FUNCTION evt_automatic_restart_point() RETURNS event_trigger > LANGUAGE plpgsql > AS $$ > BEGIN > PERFORM pg_create_restore_point(tg_tag); > END > $$; > > CREATE EVENT TRIGGER automatic_restart_point ON ddl_command_start > EXECUTE PROCEDURE evt_automatic_restart_point(); > > Are there any concerns about this?
Mumble. Re-reading the implementation in standard_ProcessUtility, I wonder what is PROCESS_UTILITY_QUERY_NONATOMIC -- there seems to be a maze through SPI that determines whether this flag is set or not, which could affect whether the event trigger is useful. Are utilities executed through a procedure detected by event triggers? If so, then this mechanism seems good enough to me. But if there's a way to sneak utility commands (DROP TABLE) without the event trigger being invoked, then no (and in that case maybe it's just a bug in procedures and we can still not include this patch). (Grepping for "atomic" is unsurprisingly unhelpful. I really wish we didn't use plain words as struct member names ...) On the TRUNCATE case it's a bit annoying that you can't do it with event triggers -- you have to create individual regular triggers on truncate for each table (so you probably need yet another event trigger that creates such triggers). -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
