Re: Improving executor performance - tidbitmap

On Wed, Jul 13, 2016 at 8:06 PM, Andres Freund <andres@anarazel.de> wrote:
> I've quickly hacked up an alternative linear addressing hashtable
> implementation. And the improvements are quite remarkable.
>
> Example Query:
> EXPLAIN ANALYZE SELECT SUM(l_extendedprice) FROM lineitem WHERE (l_shipdate >= '1995-01-01'::date) AND (l_shipdate <=
'1996-12-31'::date);

> timing without analyze: 4136.425 4101.873 4177.441
>
> after:

> timing without analyze: 2647.364 2674.456 2680.197
>
> as you can see the the time for the bitmap index scan goes from 2461.622
> to 952.161.

That's pretty great. I wonder what this would look like with a BRIN
index, since l_shipdate looks like a good candidate for BRIN indexing.


-- 
Peter Geoghegan