Re: Record a Bitmapset of non-pruned partitions

On Mon, Jul 12, 2021 at 11:47 AM David Rowley <dgrowleyml(at)gmail(dot)com> wrote:
> v3 patches

0001 looks mostly fine, except I thought the following could be worded
to say that the bitmap members are offsets into the part_rels array.
To avoid someone confusing them with RT indexes, for example.

+ Bitmapset *live_parts; /* Bitmap with members to indicate which
+ * partitions survived partition pruning. */

On 0002:

interleaved_parts idea looks clever. I wonder if you decided that
it's maybe not worth setting that field in the joinrel's
PartitionBoundInfos? For example, adding the code that you added in
create_list_bounds() also in merge_list_bounds().

... The definition of interleaved
+ * is any partition that can contain multiple different values where exists at
+ * least one other partition which could contain a value which is between the
+ * multiple possible values in the other partition.

The sentence sounds a bit off starting at "...where exists". How about:

"A partition is considered interleaved if it contains multiple values
such that there exists at least one other partition containing a value
that lies between those values [ in terms of partitioning-defined
ordering ]."

Looks fine otherwise.

--
Amit Langote
EDB: http://www.enterprisedb.com