Re: encourging bitmap AND

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