Horton

Re: Improper const-evaluation of HAVING with grouping sets and subquery pullup

Andrew Gierth <andrew@tao11.riddles.org.uk>

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From: Andrew Gierth <andrew@tao11.riddles.org.uk>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>, Pg Bugs <pgsql-bugs@postgresql.org>
Date: 2017-10-16T15:11:24Z
Lists: pgsql-bugs 
>>>>> "Tom" == Tom Lane <tgl@sss.pgh.pa.us> writes:

 >> Further experimentation reveals that this change has the effect of
 >> blocking constant-folding in aggregate input expressions that refer
 >> to constant outputs of the subquery. Is it worth doing anything
 >> about that?

 Tom> Uh ... but I thought the point here is that the outputs aren't
 Tom> really constant in the presence of grouping sets.

select x, y, sum(z) from (select 1 as x, 2 as y, 3 as z) s
 group by grouping sets (x,y);

x and y aren't constants, but z is.

-- 
Andrew (irc:RhodiumToad)

Commits

  1. Fix incorrect handling of subquery pullup in the presence of grouping sets.

  2. Make setrefs.c match by ressortgroupref even for plain Vars.

  3. Make the upper part of the planner work by generating and comparing Paths.