Re: updated hash functions for postgresql v1 - Mailing list pgsql-patches

On Sun, 2007-10-28 at 13:19 -0700, CK Tan wrote:
> Hi, this query on TPCH 1G data gets about 5% improvement.

> select count (*) from (select l_orderkey, l_partkey, l_comment,
> count(l_tax) from lineitem group by 1, 2, 3) tmpt;

> On Oct 28, 2007, at 1:17 PM, Luke Lonergan wrote:
>
> > We just applied this and saw a 5 percent speedup on a hash
> > aggregation query with four colums in a 'group by' clause run
> > against a single TPC-H table (lineitem).
> >
> > CK - can you post the query?

Is this on Postgres or Greenplum?


That looks like quite a wide set of columns.

Sounds good though. Can we get any more measurements in?

--
  Simon Riggs
  2ndQuadrant  http://www.2ndQuadrant.com