| From: | Bruce Momjian <bruce(at)momjian(dot)us> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Michael Fuhr <mike(at)fuhr(dot)org>, Bruno Wolff III <bruno(at)wolff(dot)to>, Martin Lesser <ml-pgsql(at)bettercom(dot)de>, Stephan Szabo <sszabo(at)megazone(dot)bigpanda(dot)com>, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Effects of cascading references in foreign keys |
| Date: | 2006-08-22 03:50:02 |
| Message-ID: | 200608220350.k7M3o2s14894@momjian.us |
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| Lists: | pgsql-performance |
Tom Lane wrote:
> 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.
Would someone please research this? Thanks.
--
Bruce Momjian bruce(at)momjian(dot)us
EnterpriseDB http://www.enterprisedb.com
+ If your life is a hard drive, Christ can be your backup. +
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