Re: Trigger function cost

From: Glyn Astill <glynastill(at)yahoo(dot)co(dot)uk>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: Trigger function cost
Date: 2009-04-09 16:45:23
Message-ID: 726087.12777.qm@web23605.mail.ird.yahoo.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-general


> From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
>
> > Is there any reason to mess with this?
>
> No. The planner doesn't actually bother to figure the
> cost of triggers
> anyway, since presumably every correct plan will fire the
> same set of
> triggers. So even if you had a more accurate cost estimate
> than that
> one, it wouldn't get used for anything.
>

Excellent, that's good with me.

> Now, for ordinary non-trigger functions, it might be worth
> paying
> some attention to the cost estimate. "1" is
> intended to denote the
> cost of a reasonably simple C function, so PL functions
> should pretty
> much always have costs that are large multiples of that.
> 100 is a
> reasonable default, but if you know better you can put
> something else.
>

Cool, I'll leave it alone for now then, interesting stuff, thanks Tom.

In response to

Browse pgsql-general by date

  From Date Subject
Next Message Aurimas Černius 2009-04-09 16:54:43 Re: complicated query (newbie..)
Previous Message Sam Mason 2009-04-09 16:40:10 Re: ON condition in LEFT OUTER JOIN doesn't work?!