Faster partition pruning

Add a new module backend/partitioning/partprune.c, implementing a more
sophisticated algorithm for partition pruning.  The new module uses each
partition's "boundinfo" for pruning instead of constraint exclusion,
based on an idea proposed by Robert Haas of a "pruning program": a list
of steps generated from the query quals which are run iteratively to
obtain a list of partitions that must be scanned in order to satisfy
those quals.

At present, this targets planner-time partition pruning, but there exist
further patches to apply partition pruning at execution time as well.

This commit also moves some definitions from include/catalog/partition.h
to a new file include/partitioning/partbounds.h, in an attempt to
rationalize partitioning related code.

Authors: Amit Langote, David Rowley, Dilip Kumar
Reviewers: Robert Haas, Kyotaro Horiguchi, Ashutosh Bapat, Jesper Pedersen.
Discussion: https://postgr.es/m/098b9c71-1915-1a2a-8d52-1a7a50ce79e8@lab.ntt.co.jp

1 files changed, 38 insertions, 18 deletions

diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index d2e4aa3c2f4..9287baaedc0 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -2150,6 +2150,38 @@ _copyMergeAction(const MergeAction *from)
 	return newnode;
 }
 
+/*
+ * _copyPartitionPruneStepOp
+ */
+static PartitionPruneStepOp *
+_copyPartitionPruneStepOp(const PartitionPruneStepOp *from)
+{
+	PartitionPruneStepOp *newnode = makeNode(PartitionPruneStepOp);
+
+	COPY_SCALAR_FIELD(step.step_id);
+	COPY_SCALAR_FIELD(opstrategy);
+	COPY_NODE_FIELD(exprs);
+	COPY_NODE_FIELD(cmpfns);
+	COPY_BITMAPSET_FIELD(nullkeys);
+
+	return newnode;
+}
+
+/*
+ * _copyPartitionPruneStepCombine
+ */
+static PartitionPruneStepCombine *
+_copyPartitionPruneStepCombine(const PartitionPruneStepCombine *from)
+{
+	PartitionPruneStepCombine *newnode = makeNode(PartitionPruneStepCombine);
+
+	COPY_SCALAR_FIELD(step.step_id);
+	COPY_SCALAR_FIELD(combineOp);
+	COPY_NODE_FIELD(source_stepids);
+
+	return newnode;
+}
+
 /* ****************************************************************
  *						relation.h copy functions
  *
@@ -2278,21 +2310,6 @@ _copyAppendRelInfo(const AppendRelInfo *from)
 }
 
 /*
- * _copyPartitionedChildRelInfo
- */
-static PartitionedChildRelInfo *
-_copyPartitionedChildRelInfo(const PartitionedChildRelInfo *from)
-{
-	PartitionedChildRelInfo *newnode = makeNode(PartitionedChildRelInfo);
-
-	COPY_SCALAR_FIELD(parent_relid);
-	COPY_NODE_FIELD(child_rels);
-	COPY_SCALAR_FIELD(part_cols_updated);
-
-	return newnode;
-}
-
-/*
  * _copyPlaceHolderInfo
  */
 static PlaceHolderInfo *
@@ -5076,6 +5093,12 @@ copyObjectImpl(const void *from)
 		case T_MergeAction:
 			retval = _copyMergeAction(from);
 			break;
+		case T_PartitionPruneStepOp:
+			retval = _copyPartitionPruneStepOp(from);
+			break;
+		case T_PartitionPruneStepCombine:
+			retval = _copyPartitionPruneStepCombine(from);
+			break;
 
 			/*
 			 * RELATION NODES
@@ -5095,9 +5118,6 @@ copyObjectImpl(const void *from)
 		case T_AppendRelInfo:
 			retval = _copyAppendRelInfo(from);
 			break;
-		case T_PartitionedChildRelInfo:
-			retval = _copyPartitionedChildRelInfo(from);
-			break;
 		case T_PlaceHolderInfo:
 			retval = _copyPlaceHolderInfo(from);
 			break;