On Oct 29, 2005, at 9:48 AM, Bruno Wolff III wrote:
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On Sat, Oct 29, 2005 at 13:10:31 +0200,
Martin Lesser <[EMAIL PROTECTED]> wrote:
Which effects have UPDATEs on REFERENCEd TABLEs when only columns
in the
referenced table are updated which are not part of the FOREIGN KEY
constraint?
In 8.1 there is a check to see if the foreign key value has changed
and if
not a trigger isn't queued. In the currently released versions any
update
will fire triggers.
The check in comment for trigger.c didn't say if this optimization
applied
to both referencing and referenced keys or just one of those.
If you need to know more you can look at the code at:
http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/
for trigger.c.
It seems like this warrants an item somewhere in the release notes,
and I'm not currently seeing it (or a related item) anywhere. Perhaps
E.1.3.1 (Performance Improvements)? For some of the more extreme
UPDATE scenarios I've seen, this could be a big win.
--
Thomas F. O'Connell
Co-Founder, Information Architect
Sitening, LLC
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