| From: | "Scott Marlowe" <scott(dot)marlowe(at)gmail(dot)com> |
|---|---|
| To: | "Ow Mun Heng" <Ow(dot)Mun(dot)Heng(at)wdc(dot)com> |
| Cc: | pgsql-general(at)postgresql(dot)org |
| Subject: | Re: forcing use of more indexes (bitmap AND) |
| Date: | 2008-03-14 06:50:29 |
| Message-ID: | dcc563d10803132350w3ce93766x727cb82df4a7d044@mail.gmail.com |
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| Thread: | |
| Lists: | pgsql-general |
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.
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