| From: | Kevin Grittner <kgrittn(at)ymail(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Antonin Houska <antonin(dot)houska(at)gmail(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Reference to parent query from ANY sublink |
| Date: | 2013-12-11 21:48:09 |
| Message-ID: | 1386798489.91295.YahooMailNeo@web162903.mail.bf1.yahoo.com |
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| Lists: | pgsql-hackers |
Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> FWIW, that plan isn't obviously wrong; if it is broken, most
> likely the reason is that the HashAggregate is incorrectly
> unique-ifying the lower table. (Unfortunately, EXPLAIN doesn't
> show enough about the HashAgg to know what it's doing exactly.)
Yeah, I found myself wishing for an EXPLAIN option that would show
that.
> The cost of the HashAggregate is estimated higher, though, which
> suggests that maybe it's distinct'ing on two columns where the
> bogus plan only does one.
FWIW, I noticed that the actual row counts suggested that, too.
--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
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