| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Kevin Grittner <kgrittn(at)ymail(dot)com> |
| 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 23:13:23 |
| Message-ID: | 16119.1386803603@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
Kevin Grittner <kgrittn(at)ymail(dot)com> writes:
> 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.
It's not hard to do ... how about the attached?
I chose to print grouping keys for both Agg and Group nodes, and to
show them unconditionally. There's some case maybe for only including
them in verbose mode, but since sort keys are shown unconditionally,
it seemed more consistent this way.
regards, tom lane
| Attachment | Content-Type | Size |
|---|---|---|
| explain-show-grouping-keys.patch | text/x-diff | 11.6 KB |
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