Initialize ExprStates once in run-time partition pruning

Instead of doing ExecInitExpr every time a Param needs to be evaluated
in run-time partition pruning, do it once during run-time pruning
set-up and cache the exprstate in PartitionPruneContext, saving a lot of
work.

Author: David Rowley
Reviewed-by: Amit Langote, Álvaro Herrera
Discussion: https://postgr.es/m/CAKJS1f8-x+q-90QAPDu_okhQBV4DPEtPz8CJ=m0940GyT4DA4w@mail.gmail.com

1 files changed, 9 insertions, 0 deletions

diff --git a/src/include/partitioning/partprune.h b/src/include/partitioning/partprune.h
index a5568abce65..c9fe95dc30c 100644
--- a/src/include/partitioning/partprune.h
+++ b/src/include/partitioning/partprune.h
@@ -50,8 +50,17 @@ typedef struct PartitionPruneContext
 	 * are not safe to use until the executor is running.
 	 */
 	Bitmapset  *safeparams;
+
+	/*
+	 * Array of ExprStates, indexed as per PruneCtxStateIdx; one for each
+	 * partkey in each pruning step.  Allocated if planstate is non-NULL,
+	 * otherwise NULL.
+	 */
+	ExprState **exprstates;
 } PartitionPruneContext;
 
+#define PruneCxtStateIdx(partnatts, step_id, keyno) \
+	((partnatts) * (step_id) + (keyno))
 
 extern List *make_partition_pruneinfo(PlannerInfo *root, List *partition_rels,
 						 List *subpaths, List *prunequal);