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help / color / mirror / Atom feedFrom: David Fetter <david@fetter.org>
To: Corey Huinker <corey.huinker@gmail.com>
Cc: surafel3000@gmail.com
Cc: cmt@burggraben.net
Cc: pgsql-hackers@lists.postgresql.org
Subject: Re: COPY FROM WHEN condition
Date: Thu, 11 Oct 2018 17:35:05 +0200
Message-ID: <20181011153505.GL6157@fetter.org> (raw)
In-Reply-To: <CADkLM=dmvGSpZ+h_CzFoGeuzH7mZT3TLttx-ikc+UYw_e6L2jg@mail.gmail.com>
References: <CALAY4q_DdpWDuB5-Zyi-oTtO2uSk8pmy+dupiRe3AvAc++1imA@mail.gmail.com>
<20181011085925.5zopu7jvxzs5c4xq@squirrel.exwg.net>
<CALAY4q__47MCCgspPVETAeSpJYfaYGpwH2diDGp5KjfSxTma4A@mail.gmail.com>
<CADkLM=dmvGSpZ+h_CzFoGeuzH7mZT3TLttx-ikc+UYw_e6L2jg@mail.gmail.com>
On Thu, Oct 11, 2018 at 05:12:48AM -0400, Corey Huinker wrote:
> On Thu, Oct 11, 2018 at 5:04 AM Surafel Temesgen <surafel3000@gmail.com>
> wrote:
>
> >
> >
> > On Thu, Oct 11, 2018 at 12:00 PM Christoph Moench-Tegeder <
> > cmt@burggraben.net> wrote:
> >
> >> You can:
> >> COPY ( query ) TO 'filename';
> >>
> > it is for COPY FROM
> >
> > regards
> > Surafel
> >
>
> It didn't get far, but you may want to take a look at a rejected patch for
> copy_srf() (set returning function)
> https://www.postgresql.org/message-id/CADkLM%3DdoeiWQX4AGtDNG4PsWfSXz3ai7kY%3DPZm3sUhsUeev9Bg%40mail...
> https://commitfest.postgresql.org/12/869/
>
> Having a set returning function gives you the full expressiveness of SQL,
> at the cost of an extra materialization step.
I wonder whether something JIT-like could elide this. A very
interesting subset of such WHEN clauses could be pretty
straight-forward to implement in a pretty efficient way.
Best,
David.
--
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778
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To: pgsql-hackers@postgresql.org
Cc: david@fetter.org, corey.huinker@gmail.com, surafel3000@gmail.com, cmt@burggraben.net, pgsql-hackers@lists.postgresql.org
Subject: Re: COPY FROM WHEN condition
In-Reply-To: <20181011153505.GL6157@fetter.org>
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