From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
---|---|
To: | Andrew Gierth <andrew(at)tao11(dot)riddles(dot)org(dot)uk> |
Cc: | Andreas Karlsson <andreas(at)proxel(dot)se>, David Fetter <david(at)fetter(dot)org>, Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Early WIP/PoC for inlining CTEs |
Date: | 2019-01-27 15:21:55 |
Message-ID: | 744.1548602515@sss.pgh.pa.us |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
Andrew Gierth <andrew(at)tao11(dot)riddles(dot)org(dot)uk> writes:
> I'm not sure we should nail down the rule that the absence of NOT
> MATERIALIZED will mean a multiply-referenced CTE is evaluated once. One
> would hope that in the future the planner might be taught to inline or
> not in that case depending on cost. I think it makes more sense to say
> that we never inline if MATERIALIZED is specified, that we always inline
> if NOT MATERIALIZED is specified, and that if neither is specified the
> planner will choose (but perhaps note that currently it always chooses
> only based on refcount).
I have no objection to documenting it like that; I just don't want us
to go off into the weeds trying to actually implement something smarter
for v12.
regards, tom lane
From | Date | Subject | |
---|---|---|---|
Next Message | Dmitry Dolgov | 2019-01-27 17:17:46 | Re: Index Skip Scan |
Previous Message | Tom Lane | 2019-01-27 15:17:43 | Re: Allowing extensions to supply operator-/function-specific info |