Re: [HACKERS] Gather Merge - Mailing list pgsql-hackers

From Peter Geoghegan
Subject Re: [HACKERS] Gather Merge
Date
Msg-id CAM3SWZQ4hUYU7fE56RR4ScXbiC1S-qTatNEp0i0qaymK9Od_GQ@mail.gmail.com
Whole thread Raw
In response to Re: [HACKERS] Gather Merge  (Rushabh Lathia <rushabh.lathia@gmail.com>)
List pgsql-hackers
On Tue, Jan 17, 2017 at 4:26 AM, Rushabh Lathia
<rushabh.lathia@gmail.com> wrote:
> Another observation is, HashAggregate (case 1) is performs better compare to
> GroupAggregate (case 2), but still it doesn't justify the cost difference of
> those two.

It may not be the only issue, or even the main issue, but I'm fairly
suspicious of the fact that cost_sort() doesn't distinguish between
the comparison cost of text and int4, for example.

-- 
Peter Geoghegan



pgsql-hackers by date:

Previous
From: Alvaro Herrera
Date:
Subject: Re: [HACKERS] [COMMITTERS] pgsql: Generate fmgr prototypes automatically
Next
From: Robert Haas
Date:
Subject: Re: [HACKERS] Too many autovacuum workers spawned during forced auto-vacuum