Re: Effects of cascading references in foreign keys
Tom Lane <tgl@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Michael Fuhr <mike@fuhr.org>
Cc: Bruno Wolff III <bruno@wolff.to>, Martin Lesser <ml-pgsql@bettercom.de>, Stephan Szabo <sszabo@megazone.bigpanda.com>, pgsql-performance@postgresql.org
Date: 2005-10-29T18:35:25Z
Lists: pgsql-performance
I wrote: > Looking at this, I wonder if there isn't a bug or at least an > inefficiency in 8.1. The KeysEqual short circuit tests are still there > in ri_triggers.c; aren't they now redundant with the test in triggers.c? > And don't they need to account for the special case mentioned in the > comment in triggers.c, that the RI check must still be done if we are > looking at a row updated by the same transaction that created it? OK, I take back the possible-bug comment: the special case only applies to the FK-side triggers, which is to say RI_FKey_check, and that routine doesn't attempt to skip the check on equal old/new keys. I'm still wondering though if the KeysEqual tests in the other RI triggers aren't now a waste of cycles. regards, tom lane