On Mon, Aug 17, 2015 at 9:40 AM, Kouhei Kaigai <kaigai@ak.jp.nec.com> wrote:
> I think SortSupport logic provides a reasonable way to solve this
> kind of problem. For example, btint4sortsupport() informs a function
> pointer of the fast version of comparator (btint4fastcmp) which takes
> two Datum argument without indirect memory reference.
> This mechanism will also make sense for HashAggregate logic, to reduce
> the cost of function invocations.
>
> Please comment on the idea I noticed here.
It's possible that this can work, but it might be a good idea to run
'perf' on this query and find out where the CPU time is actually
going. That might give you a clearer picture of why the HashAggregate
is slow.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
