Even if the joining relations don't have exactly the same partition bounds,

partitionwise join can still be applied by using an advanced

partition-matching algorithm. For both the joining relations, the algorithm

checkswether every partition of one joining relation only matches one

checkswhether every partition of one joining relation only matches one

partition of the other joining relation at most. In such a case the join

between the joining relations can be broken down into joins between the

matching partitions. The join relation can then beconsiderd partitioned.

matching partitions. The join relation can then beconsidered partitioned.

The algorithm produces the pairs of the matching partitions, plus the

partition bounds for the join relation, to allow partitionwise join for

computing the join. The algorithm is implemented in partition_bounds_merge().