Re: Rule vs Trigger

"Albe Laurenz" <all@adv.magwien.gv.at> writes:
> Richard Broersma Jr wrote:
>> My understanding is that Triggers offer better performance
>> than rules do.

> A trigger FOR EACH STATEMENT will execute the trigger function
> for each row affacted by the statement.

Huh?  That would be true for a FOR EACH ROW trigger, but a STATEMENT
trigger fires once per statement.

> A rule would only
> execute one additional statement. So if you can do it with a rule
> conveniently, the rule will probably be faster.

I find this unlikely.  The overhead involved in setting up a rule
is probably larger than that involved in calling a trigger.
The real question is whether you need access to the modified data
or not --- a statement-level trigger doesn't currently get that.

            regards, tom lane