On Mon, Jul 08, 2019 at 10:37:37PM -0400, Bruce Momjian wrote: > On Fri, Jul 5, 2019 at 09:20:07PM +0000, PG Doc comments form wrote: >> In the documentation for Postgres 11 table partitioning, there is no mention >> of the requirement that the Primary Key of a partitioned table must contain >> the partition key. >> In fact the documentation on primary keys is so light that I am not even >> 100% sure the above is correct. If the following table is not possible in >> Postgres 11, the documentation should find some way to make that clear. >> >> I believe this should be documented in section "5.10.2.3. Limitations" > > Can someone comment on this? CC to hackers.
Yep, that's the case: =# CREATE TABLE parent_tab (id int, id2 int primary key) PARTITION BY RANGE (id); ERROR: 0A000: insufficient columns in PRIMARY KEY constraint definition DETAIL: PRIMARY KEY constraint on table "parent_tab" lacks column "id" which is part of the partition key. LOCATION: DefineIndex, indexcmds.c:894
same is valid for UNIQUE constraint also.
postgres=# CREATE TABLE parent_tab (id int, id2 int unique) PARTITION BY RANGE (id); ERROR: insufficient columns in UNIQUE constraint definition DETAIL: UNIQUE constraint on table "parent_tab" lacks column "id" which is part of the partition key.
I agree with the report here that adding one sentence to 5.10.2.3 which is for the limitations of declarative partitioning would be a good idea. We don't mention the limitation in CREATE TABLE either (which would be rather incorrect IMO).
Attached is an idea of patch for the documentation, using this wording: + <listitem> + <para> + When defining a primary key on a partitioned table, the primary + key column must be included in the partition key. + </para> + </listitem> If somebody has any better idea for that paragraph, please feel free. -- Michael