Re: Rules for trigger execution

Richard Huxton wrote:

> On Wednesday 29 Jan 2003 11:11 am, pginfo wrote:
> > Hi,
> >
> > Is it possible in pg to define rules for trigger execution.
> > I have a table with namy fields and have defined trigger ( in PL/SQL) on
> > updating.
> >
> > If I try to update one field from the table and it is not includet in
> > trigger calculation, pg takes about 15 min for updating 700K records.
> >
> > If I do not have trigger installed all is ok as performance.
> >
> > My Question is how to define that I need trigger execution by changin
> > only some fields from table?
>
> Unfortunately, you can't specify firing triggers only on changes to certain
> columns (although the docs say this is part of the SQL 99 spec).
>
> > Will be trigger execution faster if I write it in C ?
>
> Almost certainly, although how much faster depends on what the trigger is
> doing. The first thing I'd do is test which columns have changed and exit the
> trigger function unless it really has to do some work.
>

I do the same, but it looks that pg calls slow the trigger.No mather if the
trigger do what else.

regards,
ivan.

> --
> Richard Huxton