pgsql: Move PartitioPruneInfo out of plan nodes into PlannedStmt

Move PartitioPruneInfo out of plan nodes into PlannedStmt

The planner will now add a given PartitioPruneInfo to
PlannedStmt.partPruneInfos instead of directly to the
Append/MergeAppend plan node. What gets set instead in the
latter is an index field which points to the list element
of PlannedStmt.partPruneInfos containing the PartitioPruneInfo
belonging to the plan node.

A later commit will make AcquireExecutorLocks() do the initial
partition pruning to determine a minimal set of partitions to be
locked when validating a plan tree and it will need to consult the
PartitioPruneInfos referenced therein to do so. It would be better
for the PartitioPruneInfos to be accessible directly than requiring
a walk of the plan tree to find them, which is easier when it can be
done by simply iterating over PlannedStmt.partPruneInfos.

Author: Amit Langote <amitlangote09(at)gmail(dot)com>
Discussion: https://postgr.es/m/CA+HiwqFGkMSge6TgC9KQzde0ohpAycLQuV7ooitEEpbKB0O_mg@mail.gmail.com

Branch
------
master

Details
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https://git.postgresql.org/pg/commitdiff/ec386948948c1708c0c28c48ef08b9c4dd9d47cc

Modified Files
--------------
src/backend/executor/execMain.c | 1 +
src/backend/executor/execParallel.c | 1 +
src/backend/executor/execPartition.c | 18 ++++++++-
src/backend/executor/execUtils.c | 1 +
src/backend/executor/nodeAppend.c | 5 ++-
src/backend/executor/nodeMergeAppend.c | 5 ++-
src/backend/optimizer/plan/createplan.c | 24 ++++++------
src/backend/optimizer/plan/planner.c | 1 +
src/backend/optimizer/plan/setrefs.c | 67 ++++++++++++++++++---------------
src/backend/partitioning/partprune.c | 19 +++++++---
src/include/catalog/catversion.h | 2 +-
src/include/executor/execPartition.h | 4 +-
src/include/nodes/execnodes.h | 1 +
src/include/nodes/pathnodes.h | 6 +++
src/include/nodes/plannodes.h | 14 +++++--
src/include/partitioning/partprune.h | 8 ++--
16 files changed, 114 insertions(+), 63 deletions(-)