Ashish Arte <[EMAIL PROTECTED]> writes: > We recently upgraded to Postgres 7.4 from 7.3.9 and noticed that the > foreign key constraints compile noticeably faster. In 7.3 the > constraints would typically take more than an hour to run on our > production data. Now they take a minute or two.
> Can anybody explain such a major performance improvement ? Hey, we do do some work on this thing from time to time ;-) Probably you are talking about this: 2003-10-06 12:38 tgl * src/: backend/commands/tablecmds.c, backend/utils/adt/ri_triggers.c, include/commands/trigger.h: During ALTER TABLE ADD FOREIGN KEY, try to check the existing rows using a single LEFT JOIN query instead of firing the check trigger for each row individually. Stephan Szabo, with some kibitzing from Tom Lane and Jan Wieck. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]