Re: Missed LIMIT clause pushdown in FDW API - Mailing list pgsql-general

From Tom Lane
Subject Re: Missed LIMIT clause pushdown in FDW API
Date
Msg-id 31924.1459344783@sss.pgh.pa.us
Whole thread Raw
In response to Re: Missed LIMIT clause pushdown in FDW API  (Merlin Moncure <mmoncure@gmail.com>)
Responses Re: Missed LIMIT clause pushdown in FDW API  (Merlin Moncure <mmoncure@gmail.com>)
Re: Missed LIMIT clause pushdown in FDW API  (Alexander Reshetov <alexander.v.reshetov@gmail.com>)
List pgsql-general
Merlin Moncure <mmoncure@gmail.com> writes:
> On Wed, Mar 30, 2016 at 3:52 AM, Alexander Reshetov
> <alexander.v.reshetov@gmail.com> wrote:
>> As far as I know there is no LIMIT clause pushdown in FDW API.
>> Is there some reasons not to support LIMIT clause pushdown?

It was impossible to do it before 3fc6e2d7f5b652b4, committed 3 weeks
ago.  Now that that infrastructure exists, someone might look into
using it for this purpose ... but not before 9.7 at the earliest.

> Working for me on 9.5 with postgres_fdw...

Really?  It's true that postgres_fdw won't fetch more rows than it
actually needs from the remote --- but that's not the same as telling
the remote planner to prefer a fast-start plan.

            regards, tom lane


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