From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
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To: | Ben <midfield(at)gmail(dot)com> |
Cc: | pgsql-performance(at)postgresql(dot)org |
Subject: | Re: encourging bitmap AND |
Date: | 2010-12-23 20:52:12 |
Message-ID: | 27812.1293137532@sss.pgh.pa.us |
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Lists: | pgsql-performance |
Ben <midfield(at)gmail(dot)com> writes:
> i have a schema similar to the following
> create index foo_s_idx on foo using btree (s);
> create index foo_e_idx on foo using btree (e);
> i want to do queries like
> select * from foo where 150 between s and e;
That index structure is really entirely unsuited to what you want to do,
so it's not surprising that the planner isn't impressed with the idea of
a bitmap AND.
I'd suggest setting up something involving a gist index over an
interval-ish datatype. The PERIOD datatype that Jeff Davis is fooling
with would do what you want --- see
http://pgfoundry.org/projects/temporal
http://thoughts.j-davis.com/2009/11/08/temporal-keys-part-2/
If you don't want any add-on parts involved, you could fake it by using
a box or possibly lseg.
regards, tom lane
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