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@gmail.com>
Discussion: https://postgr.es/m/CA+HiwqFGkMSge6TgC9KQzde0ohpAycLQuV7ooitEEpbKB0O_mg@mail.gmail.com

1 files changed, 13 insertions, 11 deletions

diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index 5013ac3377f..66139928e81 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -1203,7 +1203,6 @@ create_append_plan(PlannerInfo *root, AppendPath *best_path, int flags)
 	ListCell   *subpaths;
 	int			nasyncplans = 0;
 	RelOptInfo *rel = best_path->path.parent;
-	PartitionPruneInfo *partpruneinfo = NULL;
 	int			nodenumsortkeys = 0;
 	AttrNumber *nodeSortColIdx = NULL;
 	Oid		   *nodeSortOperators = NULL;
@@ -1354,6 +1353,9 @@ create_append_plan(PlannerInfo *root, AppendPath *best_path, int flags)
 		subplans = lappend(subplans, subplan);
 	}
 
+	/* Set below if we find quals that we can use to run-time prune */
+	plan->part_prune_index = -1;
+
 	/*
 	 * If any quals exist, they may be useful to perform further partition
 	 * pruning during execution.  Gather information needed by the executor to
@@ -1377,16 +1379,14 @@ create_append_plan(PlannerInfo *root, AppendPath *best_path, int flags)
 		}
 
 		if (prunequal != NIL)
-			partpruneinfo =
-				make_partition_pruneinfo(root, rel,
-										 best_path->subpaths,
-										 prunequal);
+			plan->part_prune_index = make_partition_pruneinfo(root, rel,
+															  best_path->subpaths,
+															  prunequal);
 	}
 
 	plan->appendplans = subplans;
 	plan->nasyncplans = nasyncplans;
 	plan->first_partial_plan = best_path->first_partial_path;
-	plan->part_prune_info = partpruneinfo;
 
 	copy_generic_path_info(&plan->plan, (Path *) best_path);
 
@@ -1425,7 +1425,6 @@ create_merge_append_plan(PlannerInfo *root, MergeAppendPath *best_path,
 	List	   *subplans = NIL;
 	ListCell   *subpaths;
 	RelOptInfo *rel = best_path->path.parent;
-	PartitionPruneInfo *partpruneinfo = NULL;
 
 	/*
 	 * We don't have the actual creation of the MergeAppend node split out
@@ -1518,6 +1517,9 @@ create_merge_append_plan(PlannerInfo *root, MergeAppendPath *best_path,
 		subplans = lappend(subplans, subplan);
 	}
 
+	/* Set below if we find quals that we can use to run-time prune */
+	node->part_prune_index = -1;
+
 	/*
 	 * If any quals exist, they may be useful to perform further partition
 	 * pruning during execution.  Gather information needed by the executor to
@@ -1541,13 +1543,13 @@ create_merge_append_plan(PlannerInfo *root, MergeAppendPath *best_path,
 		}
 
 		if (prunequal != NIL)
-			partpruneinfo = make_partition_pruneinfo(root, rel,
-													 best_path->subpaths,
-													 prunequal);
+			node->part_prune_index = make_partition_pruneinfo(root, rel,
+															  best_path->subpaths,
+															  prunequal);
 	}
 
 	node->mergeplans = subplans;
-	node->part_prune_info = partpruneinfo;
+
 
 	/*
 	 * If prepare_sort_from_pathkeys added sort columns, but we were told to