Re: Reference to parent query from ANY sublink

From: Kevin Grittner <kgrittn(at)ymail(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Antonin Houska <antonin(dot)houska(at)gmail(dot)com>
Cc: "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Reference to parent query from ANY sublink
Date: 2013-12-12 14:52:19
Message-ID: 1386859939.39505.YahooMailNeo@web162905.mail.bf1.yahoo.com
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Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> Hm, that means there's only one grouping column (and it's the second
> tlist entry of the child plan node).  So that seems conclusive that
> the unique-ification is being done wrong.

Further confirmation using the EXPLAIN patch with Antonin's v2
patch against the table before any EXPLAIN or ANALYZE:

 Hash Join  (cost=37.12..80.40 rows=442 width=12)
   Hash Cond: (((upper.f2)::double precision = lower.f3) AND (upper.f1 = lower.f2))
   ->  Seq Scan on subselect_tbl upper  (cost=0.00..27.70 rows=1770 width=16)
   ->  Hash  (cost=34.12..34.12 rows=200 width=12)
         ->  HashAggregate  (cost=32.12..34.12 rows=200 width=12)
               Group Key: lower.f2
               ->  Seq Scan on subselect_tbl lower  (cost=0.00..27.70 rows=1770 width=12)

The additional information is so useful, I'm all for committing
that patch.

--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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