Re: generic plans and "initial" pruning

On Wed, Oct 12, 2022 at 4:36 PM Amit Langote <amitlangote09@gmail.com> wrote:
> On Fri, Jul 29, 2022 at 1:20 PM Amit Langote <amitlangote09@gmail.com> wrote:
> > On Thu, Jul 28, 2022 at 1:27 AM Robert Haas <robertmhaas@gmail.com> wrote:
> > > 0001 adds es_part_prune_result but does not use it, so maybe the
> > > introduction of that field should be deferred until it's needed for
> > > something.
> >
> > Oops, looks like a mistake when breaking the patch.  Will move that bit to 0002.
>
> Fixed that and also noticed that I had defined PartitionPruneResult in
> the wrong header (execnodes.h).  That led to PartitionPruneResult
> nodes not being able to be written and read, because
> src/backend/nodes/gen_node_support.pl doesn't create _out* and _read*
> routines for the nodes defined in execnodes.h.  I moved its definition
> to plannodes.h, even though it is not actually the planner that
> instantiates those; no other include/nodes header sounds better.
>
> One more thing I realized is that Bitmapsets added to the List
> PartitionPruneResult.valid_subplan_offs_list are not actually
> read/write-able.  That's a problem that I also faced in [1], so I
> proposed a patch there to make Bitmapset a read/write-able Node and
> mark (only) the Bitmapsets that are added into read/write-able node
> trees with the corresponding NodeTag.  I'm including that patch here
> as well (0002) for the main patch to work (pass
> -DWRITE_READ_PARSE_PLAN_TREES build tests), though it might make sense
> to discuss it in its own thread?

Had second thoughts on the use of List of Bitmapsets for this, such
that the make-Bitmapset-Nodes patch is no longer needed.

I had defined PartitionPruneResult such that it stood for the results
of pruning for all PartitionPruneInfos contained in
PlannedStmt.partPruneInfos (covering all Append/MergeAppend nodes that
can use partition pruning in a given plan).  So, it had a List of
Bitmapset.  I think it's perhaps better for PartitionPruneResult to
cover only one PartitionPruneInfo and thus need only a Bitmapset and
not a List thereof, which I have implemented in the attached updated
patch 0002.  So, instead of needing to pass around a
PartitionPruneResult with each PlannedStmt, this now passes a List of
PartitionPruneResult with an entry for each in
PlannedStmt.partPruneInfos.

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