Re: Should we add GUCs to allow partition pruning to be disabled?

On Thu, Apr 11, 2019 at 03:34:30PM +1200, David Rowley wrote:
> On Thu, 21 Mar 2019 at 00:51, David Rowley <david(dot)rowley(at)2ndquadrant(dot)com> wrote:
> > Just so I don't forget about this, I've added it to the July 'fest.
> >
> > https://commitfest.postgresql.org/23/2065/
>
> Now that we have 428b260f8, I think the version of this that goes into
> master should be more like the attached.

I tweaked this patch some more (sorry):
- remove "currently" since that's not expected to be changed (right?);
- remove "especially";
- refer to "partition hierarchies" not "partitioning hierarchies";
- rewrite bit about "When partition pruning is not possible"

Also, I noticed awhile ago while grepping for "probably be fixed in future
releases" that some items under ddl-inherit-caveats are actually possible for
relkind=p partitions in v11. I assume those will never be implemented for
inheritence partitioning, so I propose another update to docs (if preferred,
I'll bring up on a new thread).

- unique constraints on parent table;
- FK constraints on parent table;

Note that FK constraints *referencing* a partitiond table are possible in v12
but not in v11. So if there's any finer-grained update to documentation of the
individual limitations, it'd need to be tweaked for back branches (v10 and 11).

Justin