>> > 0007: >> > This patch introduces code to check if the scanning of default partition >> > child >> > can be skipped if it's constraints are proven. >> >> If I understand correctly, this is actually a completely separate >> feature not intrinsically related to default partitioning. > > I don't see this as a new feature, since scanning the default partition > will be introduced by this series of patches only, and rather than a > feature this can be classified as a completeness of default skip > validation logic. Your thoughts?
Currently, when a partitioned table is attached, we check whether all the scans can be checked but not whether scans on some partitions can be attached. So there are two separate things:
1. When we introduce default partitioning, we need scan the default partition either when (a) any partition is attached or (b) any partition is created.
2. In any situation where scans are needed (scanning the partition when it's attached, scanning the default partition when some other partition is attached, scanning the default when a new partition is created), we can run predicate_implied_by for each partition to see whether the scan of that partition can be skipped.
Those two changes are independent. We could do (1) without doing (2) or (2) without doing (1) or we could do both. So they are separate features.
In my V25 series(patch 0005) I have only addressed half of (2) above
i.e. code to check whether the scan of a partition of default partition
can be skipped when other partition is being added. Amit Langote
has submitted[1] a separate patch(0003) to address skipping the scan
of the children of relation when it's being attached as a partition.
