On Fri, 23 Jun 2017 09:54:17 -0400 Tom Lane <[email protected]> wrote:
> Yugo Nagata <[email protected]> writes: > > 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 > > AFAIK, that's just a simple test for obvious mistakes; it's not a > property that's essential for correctness. Thanks. This is what I want to know. > > > However, I can use same expression more than once in partition key. > > ... and so, I can't get excited about extending it to expressions. > Where would you stop --- for example, are i and (i) equal? What > about (i) and (case when true then i else j end)? In principle, > the system could recognize both those identities, but it seems > silly to expend code on it just for nagware purposes. > Agreed. > regards, tom lane -- Yugo Nagata <[email protected]> -- Sent via pgsql-hackers mailing list ([email protected]) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
