Re: Declarative partitioning - another take

On 2016/11/02 16:41, Amit Langote wrote:
> Having said all that, I am open to switching to the catalogued partition
> constraints if the arguments I make above in favor of this patch are not
> all that sound.

One problem I didn't immediately see a solution for if we go with the
catalogued partition constraints is how do we retrieve a relation's
partition constraint?  There are a couple of cases where that becomes
necessary.  Consider that we are adding a partition to a partitioned table
that is itself partition.  In this case, the new partition's constraint
consists of whatever we generate from its FOR VALUES specification *ANDed*
with the parent's constraint.  We must somehow get hold of the latter.
Which of the parent's named check constraints in the pg_constraint catalog
is supposed to be the partition constraint?  With the uncatalogued
partition constraints approach, we simply generate it from the parent's
pg_class.relpartbound (or we might get the relcache copy of the same
stored in rd_partcheck).  Hmm.

Thanks,
Amit