Re: forcing use of more indexes (bitmap AND)

On Fri, 2008-03-14 at 00:50 -0600, Scott Marlowe wrote:
> On Fri, Mar 14, 2008 at 12:28 AM, Ow Mun Heng <Ow(dot)Mun(dot)Heng(at)wdc(dot)com> wrote:
> > query is something like this
> >
> > Select *
> > from v_test
> > where acode Like 'PC%'
> > and rev = '0Q'
> > and hcm = '1'
> > and mcm = 'K'
> >
> > where acode, rev, hcm, mcm are all indexes.
> >
> > Currently this query is only using the rev and mcm for the bitmapAND.
> > it then does a bitmap heap scan using the acode and the hcm indexes.
> >
> > I would like to try to see if forcing the planner to favour heavier usage of the indexes would yield faster results.
> >
> > I've tried lowering
>
> Would setting enable_bitmapscan=off do that? I'm not being sarcastic,
> I really don't know.

This is even worst as the planner would only use 1 index.