v37-0003-Teach-planner-to-only-process-unpruned-partition.patch

From 251c9f2455814e45324f34241a5b1130837c7c04 Mon Sep 17 00:00:00 2001
From: amit <amitlangote09@gmail.com>
Date: Mon, 4 Mar 2019 11:57:04 +0900
Subject: [PATCH v37 3/5] Teach planner to only process unpruned partitions

This adds a bitmapset field live_parts to RelOptInfo and stores
the partition indexes of non-dummy partitions in it, meaning it
contains indexes of only those partitions that have a non-NULL
RelOptInfo present in its parent's RelOptInfo's part_rels array.

This speeds up processing partitioned table's partitions compared
to going through the whole part_rels array in a number of places.

Partitionwise join still has to visit each member of part_rels,
because pruned children may fall on the nullable side of an outer
join and an empty Result path must be present for building the
outer join paths.
---
 src/backend/optimizer/path/joinrels.c |  3 +++
 src/backend/optimizer/plan/planner.c  | 18 +++++++++---------
 src/backend/optimizer/util/inherit.c  |  6 ++++++
 src/backend/optimizer/util/relnode.c  |  3 +++
 src/backend/partitioning/partprune.c  | 19 ++++++-------------
 src/include/nodes/pathnodes.h         |  4 ++++
 6 files changed, 31 insertions(+), 22 deletions(-)

diff --git a/src/backend/optimizer/path/joinrels.c b/src/backend/optimizer/path/joinrels.c
index 83c24a45b8..38fda5832b 100644
--- a/src/backend/optimizer/path/joinrels.c
+++ b/src/backend/optimizer/path/joinrels.c
@@ -1498,6 +1498,9 @@ try_partitionwise_join(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2,
 		populate_joinrel_with_paths(root, child_rel1, child_rel2,
 									child_joinrel, child_sjinfo,
 									child_restrictlist);
+		if (!IS_DUMMY_REL(child_joinrel))
+			joinrel->live_parts = bms_add_member(joinrel->live_parts,
+												 cnt_parts);
 	}
 
 	if (baserel1)
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index 16b0290fd4..dbb9531d6c 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -7000,7 +7000,9 @@ apply_scanjoin_target_to_paths(PlannerInfo *root,
 		int			partition_idx;
 
 		/* Adjust each partition. */
-		for (partition_idx = 0; partition_idx < rel->nparts; partition_idx++)
+		partition_idx = -1;
+		while ((partition_idx = bms_next_member(rel->live_parts,
+												partition_idx)) >= 0)
 		{
 			RelOptInfo *child_rel = rel->part_rels[partition_idx];
 			AppendRelInfo **appinfos;
@@ -7008,9 +7010,7 @@ apply_scanjoin_target_to_paths(PlannerInfo *root,
 			List	   *child_scanjoin_targets = NIL;
 			ListCell   *lc;
 
-			/* Skip processing pruned partitions. */
-			if (child_rel == NULL)
-				continue;
+			Assert(child_rel != NULL);
 
 			/* Translate scan/join targets for this child. */
 			appinfos = find_appinfos_by_relids(root, child_rel->relids,
@@ -7090,7 +7090,6 @@ create_partitionwise_grouping_paths(PlannerInfo *root,
 									PartitionwiseAggregateType patype,
 									GroupPathExtraData *extra)
 {
-	int			nparts = input_rel->nparts;
 	int			cnt_parts;
 	List	   *grouped_live_children = NIL;
 	List	   *partially_grouped_live_children = NIL;
@@ -7102,7 +7101,9 @@ create_partitionwise_grouping_paths(PlannerInfo *root,
 		   partially_grouped_rel != NULL);
 
 	/* Add paths for partitionwise aggregation/grouping. */
-	for (cnt_parts = 0; cnt_parts < nparts; cnt_parts++)
+	cnt_parts = -1;
+	while ((cnt_parts = bms_next_member(input_rel->live_parts,
+										cnt_parts)) >= 0)
 	{
 		RelOptInfo *child_input_rel = input_rel->part_rels[cnt_parts];
 		PathTarget *child_target = copy_pathtarget(target);
@@ -7112,9 +7113,8 @@ create_partitionwise_grouping_paths(PlannerInfo *root,
 		RelOptInfo *child_grouped_rel;
 		RelOptInfo *child_partially_grouped_rel;
 
-		/* Skip processing pruned partitions. */
-		if (child_input_rel == NULL)
-			continue;
+		/* A live partition must have a RelOptInfo. */
+		Assert(child_input_rel != NULL);
 
 		/* Input child rel must have a path */
 		Assert(child_input_rel->pathlist != NIL);
diff --git a/src/backend/optimizer/util/inherit.c b/src/backend/optimizer/util/inherit.c
index 8f7eea9fc7..150549042f 100644
--- a/src/backend/optimizer/util/inherit.c
+++ b/src/backend/optimizer/util/inherit.c
@@ -362,6 +362,12 @@ expand_partitioned_rtentry(PlannerInfo *root, RangeTblEntry *parentrte,
 		 */
 		live_parts = prune_append_rel_partitions(rel);
 
+		/*
+		 * Later steps that loop over part_rels should use these indexes
+		 * to access unpruned partitions.
+		 */
+		rel->live_parts = live_parts;
+
 		/* Expand simple_rel_array and friends to hold child objects. */
 		num_live_parts = bms_num_members(live_parts);
 		if (num_live_parts > 0)
diff --git a/src/backend/optimizer/util/relnode.c b/src/backend/optimizer/util/relnode.c
index f6fa8d27a4..75486be73c 100644
--- a/src/backend/optimizer/util/relnode.c
+++ b/src/backend/optimizer/util/relnode.c
@@ -1969,6 +1969,9 @@ build_joinrel_partition_info(RelOptInfo *joinrel, RelOptInfo *outer_rel,
 		joinrel->partexprs[cnt] = partexpr;
 		joinrel->nullable_partexprs[cnt] = nullable_partexpr;
 	}
+
+	/* Partitions will be added by try_partitionwise_join. */
+	joinrel->live_parts = NULL;
 }
 
 /*
diff --git a/src/backend/partitioning/partprune.c b/src/backend/partitioning/partprune.c
index bca26bcfbb..68f3ac6ce3 100644
--- a/src/backend/partitioning/partprune.c
+++ b/src/backend/partitioning/partprune.c
@@ -479,30 +479,23 @@ make_partitionedrel_pruneinfo(PlannerInfo *root, RelOptInfo *parentrel,
 		subpart_map = (int *) palloc(nparts * sizeof(int));
 		memset(subpart_map, -1, nparts * sizeof(Oid));
 		relid_map = (Oid *) palloc0(nparts * sizeof(Oid));
-		present_parts = NULL;
+		present_parts = bms_copy(subpart->live_parts);
 
-		for (i = 0; i < nparts; i++)
+		i = -1;
+		while ((i = bms_next_member(present_parts, i)) >= 0)
 		{
 			RelOptInfo *partrel = subpart->part_rels[i];
 			int			subplanidx;
 			int			subpartidx;
 
-			/* Skip processing pruned partitions. */
-			if (partrel == NULL)
-				continue;
-
+			Assert(partrel != NULL);
 			subplan_map[i] = subplanidx = relid_subplan_map[partrel->relid] - 1;
 			subpart_map[i] = subpartidx = relid_subpart_map[partrel->relid] - 1;
 			relid_map[i] = planner_rt_fetch(partrel->relid, root)->relid;
-			if (subplanidx >= 0)
-			{
-				present_parts = bms_add_member(present_parts, i);
 
-				/* Record finding this subplan  */
+			/* Record finding this subplan */
+			if (subplanidx >= 0)
 				subplansfound = bms_add_member(subplansfound, subplanidx);
-			}
-			else if (subpartidx >= 0)
-				present_parts = bms_add_member(present_parts, i);
 		}
 
 		/* Record the maps and other information. */
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index 253e0b7e48..4809177083 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -707,6 +707,10 @@ typedef struct RelOptInfo
 	List	   *partition_qual; /* partition constraint */
 	struct RelOptInfo **part_rels;	/* Array of RelOptInfos of partitions,
 									 * stored in the same order of bounds */
+	Bitmapset  *live_parts;		/* Indexes into part_rels of the non-NULL
+								 * RelOptInfos of unpruned partitions; exists
+								 * to avoid having to iterate over the entire
+								 * part_rels array to filter NULL entries. */
 	List	  **partexprs;		/* Non-nullable partition key expressions. */
 	List	  **nullable_partexprs; /* Nullable partition key expressions. */
 	List	   *partitioned_child_rels; /* List of RT indexes. */
-- 
2.11.0