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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andreas Karlsson <andreas@proxel.se>
Cc: Robert Haas <robertmhaas@gmail.com>
Cc: Andres Freund <andres@anarazel.de>
Cc: Thomas Munro <thomas.munro@enterprisedb.com>
Cc: Andrew Gierth <andrew@tao11.riddles.org.uk>
Cc: David Fetter <david@fetter.org>
Cc: Pg Hackers <pgsql-hackers@postgresql.org>
Subject: Re: Early WIP/PoC for inlining CTEs
Date: Thu, 17 Jan 2019 10:52:19 -0500
Message-ID: <14326.1547740339@sss.pgh.pa.us> (raw)
In-Reply-To: <00818be9-2f63-f584-efcd-d97ee0662905@proxel.se>
References: <dccb37dd-2f52-dbd7-a4c4-72a5853f4838@proxel.se>
	<e02af96a-3e25-5de4-09a4-a7ebf3452184@proxel.se>
	<8810.1542402910@sss.pgh.pa.us>
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	<CA+Tgmob=Dpje+oGCYgJCoUok=iPQarGjPqRLYS1qKzChkFfKcA@mail.gmail.com>
	<20190111181934.g5qig23o7rxubnjt@alap3.anarazel.de>
	<CAEepm=2n8hChj548H0R5g5JAx3cokpZwTqRzYhN2oVGqBONwOA@mail.gmail.com>
	<20190111190403.77ye7m5mxypxsf4l@alap3.anarazel.de>
	<CA+TgmobVMPX1wJxPaRQ=FZBzp-AQ=JWK=bzxztqwj=MsOsrnrA@mail.gmail.com>
	<00818be9-2f63-f584-efcd-d97ee0662905@proxel.se>

Andreas Karlsson <andreas@proxel.se> writes:
> On 1/11/19 8:10 PM, Robert Haas wrote:
>> WITH cte_name [[NOT] MATERIALIZED] AS (query) main_query...

> Hm, when would one want "NOT MATERIALIZED"? I am not sure I see the 
> usefulness of forcing inlining other than if we by default do not inline 
> when a CTE is referenced multiple times.

I'm also concerned about what we do if the user says NOT MATERIALIZED
but there are semantic or implementation reasons not to inline.  Either
we throw an error or do something the user didn't expect, and neither
is very nice.  So I'm not in favor of having that option.

			regards, tom lane




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  Cc: tgl@sss.pgh.pa.us, andreas@proxel.se, robertmhaas@gmail.com, andres@anarazel.de, thomas.munro@enterprisedb.com, andrew@tao11.riddles.org.uk, david@fetter.org
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