Re: help with dual indexing

Thanks Tom! You're a life-saver.

On Fri, 2004-01-23 at 17:08, Tom Lane wrote:
> Orion Henry <orion(at)trustcommerce(dot)com> writes:
> > The queries usually are in the form of, where "user_id = something and
> > event_time between something and something".
>
> > Half of my queries index off of the user_id and half index off the
> > event_time. I was thinking this would be a perfect opportunity to use a
> > dual index of (user_id,event_time) but I'm confused as to weather this
> > will help
>
> Probably. Put the user_id as the first column of the index --- if you
> think about the sort ordering of a multicolumn index, you will see why.
> With user_id first, a constraint as above describes a contiguous
> subrange of the index; with event_time first it does not.
>
> regards, tom lane
--
Orion Henry <orion(at)trustcommerce(dot)com>