The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/12/ddl-partitioning.html
Description:
With version 12 using declarative partitioning request that the column used
for patitioning is part of the PRIMARY KEY of the table as you can see in
the error message below.
ERROR: insufficient columns in PRIMARY KEY constraint definition
DETAIL: PRIMARY KEY constraint on table "ztest" lacks column "mtime" which
is part of the partition key.
If I've well understood, this was not the case in previous versions, but it
becomes mandatory in version 12 (and maybe 11 too). Such restriction is not
mentioned in the documentation for version 12 and would be suitable to be.
Best regards