From: | Tatsuro Yamada <yamada(dot)tatsuro(at)lab(dot)ntt(dot)co(dot)jp> |
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To: | pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: ORDER/GROUP BY expression not found in targetlist |
Date: | 2016-06-09 03:08:01 |
Message-ID: | 5758DD91.9050500@lab.ntt.co.jp |
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Lists: | pgsql-hackers |
Hi,
I got same error by TPC-H: Q1,4,8,12 and 17.
I've attached results of the queries.
TPC-H (thanks to Tomas Vondra)
https://github.com/tvondra/pg_tpch
Datasize
Scale Factor: 1
PG96beta1
commit: f721e94b5f360391fc3ffe183bf697a0441e9184
Regards,
Tatsuro Yamada
NTT OSS Center
On 2016/05/27 2:22, Tom Lane wrote:
> Andres Freund <andres(at)anarazel(dot)de> writes:
>> trying to reproduce a performance problem I just found:
>
>> =# CREATE TABLE twocol(col01 int, col02 int);
>> =# SELECT DISTINCT col01, col02, col01 FROM twocol ;
>> ERROR: XX000: ORDER/GROUP BY expression not found in targetlist
>> LOCATION: get_sortgroupref_tle, tlist.c:341
>
>> which appears to be a 9.6 regression, presumable fallout from the path
>> restructuring.
>
> Huh. The problem is that createplan.c is trying to apply the
> physical-tlist optimization to the seqscan underneath the aggregate
> node. That means that the output from the seqscan is just
> "col01, col02", which means that col01 can only be decorated with
> a single ressortgroupref ... but there are two ressortgrouprefs
> for it as far as the groupClause is concerned. Only one gets applied
> to the seqscan's tlist, and then later we fail because we don't find
> the other one there. Conclusions:
>
> * we need to back off the physical-tlist optimization in this case
>
> * the code that transfers sortgroupref labels onto a tlist probably
> ought to notice and complain if it's asked to put inconsistent labels
> onto the same column.
>
> I'm a little surprised that it's not discarding the third grouping
> item as redundant ... but that's probably not something to mess with
> right now. Prior versions don't appear to do that either.
>
> regards, tom lane
>
>
Attachment | Content-Type | Size |
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order_groupby_error.txt | text/plain | 5.7 KB |
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