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, 30 insertions, 0 deletions

diff --git a/src/backend/nodes/readfuncs.c b/src/backend/nodes/readfuncs.c
index 37e35685956..2812dc9646d 100644
--- a/src/backend/nodes/readfuncs.c
+++ b/src/backend/nodes/readfuncs.c
@@ -1331,6 +1331,32 @@ _readOnConflictExpr(void)
 	READ_DONE();
 }
 
+static PartitionPruneStepOp *
+_readPartitionPruneStepOp(void)
+{
+	READ_LOCALS(PartitionPruneStepOp);
+
+	READ_INT_FIELD(step.step_id);
+	READ_INT_FIELD(opstrategy);
+	READ_NODE_FIELD(exprs);
+	READ_NODE_FIELD(cmpfns);
+	READ_BITMAPSET_FIELD(nullkeys);
+
+	READ_DONE();
+}
+
+static PartitionPruneStepCombine *
+_readPartitionPruneStepCombine(void)
+{
+	READ_LOCALS(PartitionPruneStepCombine);
+
+	READ_INT_FIELD(step.step_id);
+	READ_ENUM_FIELD(combineOp, PartitionPruneCombineOp);
+	READ_NODE_FIELD(source_stepids);
+
+	READ_DONE();
+}
+
 /*
  * _readMergeAction
  */
@@ -2615,6 +2641,10 @@ parseNodeString(void)
 		return_value = _readOnConflictExpr();
 	else if (MATCH("MERGEACTION", 11))
 		return_value = _readMergeAction();
+	else if (MATCH("PARTITIONPRUNESTEPOP", 20))
+		return_value = _readPartitionPruneStepOp();
+	else if (MATCH("PARTITIONPRUNESTEPCOMBINE", 25))
+		return_value = _readPartitionPruneStepCombine();
 	else if (MATCH("RTE", 3))
 		return_value = _readRangeTblEntry();
 	else if (MATCH("RANGETBLFUNCTION", 16))