[HACKERS] Same expression more than once in partition key - Mailing list pgsql-hackers

From Yugo Nagata
Subject [HACKERS] Same expression more than once in partition key
Date
Msg-id 20170623155754.f1d25593.nagata@sraoss.co.jp
Whole thread Raw
Responses Re: [HACKERS] Same expression more than once in partition key  (Yugo Nagata <nagata@sraoss.co.jp>)
Re: [HACKERS] Same expression more than once in partition key  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Hi,

When we create a range partitioned table, we cannot use
a column more than once in the partition key.
postgres=# create table t (i int) partition by range(i,i);ERROR:  column "i" appears more than once in partition key

However, I can use same expression more than once in partition key.

postgres=# create table t (i int) partition by range((i),(i));
CREATE TABLE

Although this can be blocked by the attached parch, for example,
the following is still possible.

postgres=# create table t (i int) partition by range((i),i);
CREATE TABLE

Can these definition be a problem in the internal of partitioning?
If not, we might not need to check column that apears more than once 
in the partition key.

Regards,



-- 
Yugo Nagata <nagata@sraoss.co.jp>



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