Horton

Re: Early WIP/PoC for inlining CTEs

David Fetter <david@fetter.org>

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From: David Fetter <david@fetter.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Michael Paquier <michael@paquier.xyz>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Robert Haas <robertmhaas@gmail.com>, Andreas Karlsson <andreas@proxel.se>, Andres Freund <andres@anarazel.de>, Thomas Munro <thomas.munro@enterprisedb.com>, Andrew Gierth <andrew@tao11.riddles.org.uk>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2019-01-30T02:35:13Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Prevent inlining of multiply-referenced CTEs with outer recursive refs.

  2. Allow user control of CTE materialization, and change the default behavior.

  3. Split QTW_EXAMINE_RTES flag into QTW_EXAMINE_RTES_BEFORE/_AFTER.

  4. document when PREPARE uses generic plans

On Tue, Jan 29, 2019 at 02:52:44PM -0500, Tom Lane wrote:
> Michael Paquier <michael@paquier.xyz> writes:
> > On Mon, Jan 28, 2019 at 05:05:32PM -0500, Tom Lane wrote:
> >> Yeah, I thought about that too, but it doesn't seem like an improvement.
> >> If the query is very long (which isn't unlikely) I think people would
> >> prefer to see the option(s) up front.
> 
> > Having these options at the front of the WITH clause looks more
> > natural to me.
> 
> Well, we've managed to get agreement on the semantics of this thing,
> let's not get hung up on the syntax details.
> 
> I propose that we implement and document this as
> 
> 	WITH ctename AS [ MATERIALIZE { ON | OFF } ] ( query )

I think this would be better with parentheses like this: 

    WITH ctename [ ( MATERIALIZE { ON | OFF } ) ] AS ( query ) [, ... ]

and it's a lot easier to add more query hints later.

Best,
David.
-- 
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778

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