Hi Ashutosh,
(2019/01/15 13:29), Ashutosh Bapat wrote:
> I think, there's something better possible. Two partitioned relations
> won't use partition-wise join, if their partition schemes do not match.
> Partitioned relations with same partitioning scheme share
> PartitionScheme pointer. PartitionScheme structure should get an extra
> counter, maintaining a count of number of partitioned relations sharing
> that structure. When this counter is 1, that relation is certainly not
> going to participate in PWJ and thus need not have all the structure
> required by PWJ set up. If we use this counter coupled with
> enable_partitionwise_join flag, we can get rid of
> consider_partitionwise_join flag altogether, I think.
Interesting!
That flag was introduced to disable PWJs when whole-row Vars are
involved, as you know, so I think we need to first eliminate that
limitation, to remove that flag.
Thanks!
Best regards,
Etsuro Fujita