Horton

Re: BUG #18568: BUG: Result wrong when do group by on partition table!

Tender Wang <tndrwang@gmail.com>

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From: Tender Wang <tndrwang@gmail.com>
To: Amit Langote <amitlangote09@gmail.com>
Cc: 1105066510@qq.com, pgsql-bugs@lists.postgresql.org
Date: 2024-10-22T08:30:04Z
Lists: pgsql-bugs 
Hi Amit,

Amit Langote <amitlangote09@gmail.com> 于2024年10月22日周二 15:33写道：

>
>
> Not really.  As the documentation says, collation can be specified per
> column or per operation:
>
> https://www.postgresql.org/docs/current/collation.html
>
> In this case, the operation is partitioning.  When you specify the
> COLLATE clause for a partition key, it means that the partitioning
> logic, such as partition tuple routing, will use that collation
> instead of the column-specified or the column type's collation.
>

Since you said partition key had its own collation, and but we used column
type's collation in
 set_baserel_partition_key_exprs() as below:

partexpr = (Expr *) makeVar(varno, attno,
partkey->parttypid[cnt],
partkey->parttypmod[cnt],
partkey->parttypcoll[cnt], 0);

I think why not we directly use the partition key collation(e.g.
partcollation).


-- 
Thanks,
Tender Wang

Commits

  1. Disallow partitionwise grouping when collations don't match

  2. For partitionwise join, match on partcollation, not parttypcoll.