| From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, David Rowley <david(dot)rowley(at)2ndquadrant(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Pushdown target list below gather node (WAS Re: WIP: Upper planner pathification) |
| Date: | 2016-03-18 14:55:02 |
| Message-ID: | CA+TgmoZ0vmTZxBHruZ0ywypoRguap4Um2a7UdeH=QpjTzWCGag@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Fri, Mar 18, 2016 at 10:08 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
>> OK, I've committed something along those lines. Thanks for the
>> advice, and feel free to whack it around if you have an idea for
>> improving it further - though IMHO this is good enough for 9.6.
>
> The committed patch looks fine to me. WRT your commit-message comment
> about pushing down only parallel-safe tlist expressions, I would strongly
> advise leaving that for another day. I have some irons in the fire
> concerning ways to push down computation of index expressions (so that
> we can consistently get f(x) out of an index on f(x) rather than
> recomputing it), and managing parallel-safe expressions seems like it'd
> benefit from that infrastucture too.
Roger.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
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