From: Tom Lane <tgl@sss.pgh.pa.us>
To: Michael Fuhr <mike@fuhr.org>
Cc: Bruno Wolff III <bruno@wolff.to>
Cc: Martin Lesser <ml-pgsql@bettercom.de>
Cc: Stephan Szabo <sszabo@megazone.bigpanda.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Effects of cascading references in foreign keys
Date: Sat, 29 Oct 2005 14:35:25 -0400
Message-ID: <12097.1130610925@sss.pgh.pa.us> (raw)
In-Reply-To: <11904.1130608918@sss.pgh.pa.us>
References: <87acgszihk.fsf@nb-aspire.bettercom.de>
<20051029142432.GA79557@winnie.fuhr.org>
<20051029144947.GB21068@wolff.to>
<20051029160527.GA80135@winnie.fuhr.org>
<11904.1130608918@sss.pgh.pa.us>
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
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, mike@fuhr.org, bruno@wolff.to, ml-pgsql@bettercom.de, sszabo@megazone.bigpanda.com
Subject: Re: Effects of cascading references in foreign keys
In-Reply-To: <12097.1130610925@sss.pgh.pa.us>
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