>>>>> "Thomas" == Thomas Munro <thomas.mu...@enterprisedb.com> writes:
Thomas> So, afterTriggers.query_stack is used to handle the reentrancy Thomas> that results from triggers running further statements that Thomas> might fire triggers. It isn't used for dealing with extra Thomas> ModifyTable nodes that can appear in a plan because of wCTEs. Thomas> Could it also be used for that purpose? I think that would Thomas> only work if it is the case that each ModifyTable node begin Thomas> and then runs to completion (ie no interleaving of wCTE Thomas> execution) and then its AS trigger fires, which I'm not sure Thomas> about. There's a problem with this which I didn't see anyone mention (though I've not read the whole history); existing users of wCTEs rely on the fact that no AFTER triggers are run until _all_ modifications are completed. If you change that, then you can't use wCTEs to insert into tables with FK checks without knowing the order in which the individual wCTEs are executed, which is currently a bit vague and non-obvious (which doesn't cause issues at the moment only because nothing actually depends on the order). for example: create table foo (id integer primary key); create table foo_bar (foo_id integer references foo, bar_id integer); with i1 as (insert into foo values (1)) insert into foo_bar values (1,2),(1,3); This would fail the FK check if each insert did its own trigger firing, since the foo_bar insert is actually run _first_. Firing triggers earlier than they currently are would thus break existing working queries. -- Andrew (irc:RhodiumToad) -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
