| From: | Simon Riggs <simon(at)2ndQuadrant(dot)com> |
|---|---|
| To: | Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Simon Riggs <simon(at)2ndquadrant(dot)com>, Nicolas Barbier <nicolas(dot)barbier(at)gmail(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: a funnel by any other name |
| Date: | 2015-09-23 13:59:39 |
| Message-ID: | CANP8+jJhh92Z3gQL5Y47gNTfujL2GR+_m2P9eFWruMJc50+Uwg@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On 22 September 2015 at 21:14, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>
wrote:
> Robert Haas wrote:
> > On Tue, Sep 22, 2015 at 10:34 AM, Simon Riggs <simon(at)2ndquadrant(dot)com>
> wrote:
>
> > > For 1, Gather makes most sense.
> >
> > Yeah, I'm leaning that way myself. Amit argued for "Parallel Gather"
> > but I think that's overkill. There can't be a non-parallel gather,
> > and long names are a pain.
>
> "Gather" seems a pretty decent choice to me too, even if we only have a
> single worker (your "1"). I don't think there's much need to
> distinguish 1 from 2, is there?
>
I think so. 1 is Many->1 and the other is 1->Many.
You may wish to do an operation like a parallel merge join.
Parallel Sort -> Scatter -> Parallel Merge
--
Simon Riggs http://www.2ndQuadrant.com/
<http://www.2ndquadrant.com/>
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Tom Lane | 2015-09-23 13:59:50 | Re: TEXT vs VARCHAR join qual push down diffrence, bug or expected? |
| Previous Message | Simon Riggs | 2015-09-23 13:57:23 | Re: a funnel by any other name |