diff --git a/src/backend/executor/execPartition.c b/src/backend/executor/execPartition.c
index eb8a87fd63..eec84115a7 100644
--- a/src/backend/executor/execPartition.c
+++ b/src/backend/executor/execPartition.c
@@ -2108,7 +2108,8 @@ InitPartitionPruneContext(PartitionPruneContext *context,
 	foreach(lc, pruning_steps)
 	{
 		PartitionPruneStepOp *step = (PartitionPruneStepOp *) lfirst(lc);
-		ListCell   *lc2;
+		ListCell *lc2 = list_head(step->exprs);
+
 		int			keyno;
 
 		/* not needed for other step kinds */
@@ -2117,34 +2118,39 @@ InitPartitionPruneContext(PartitionPruneContext *context,
 
 		Assert(list_length(step->exprs) <= partnatts);
 
-		keyno = 0;
-		foreach(lc2, step->exprs)
+		for (keyno = 0; keyno < partnatts; keyno++)
 		{
-			Expr	   *expr = (Expr *) lfirst(lc2);
+			if (bms_is_member(keyno, step->nullkeys))
+				continue;
 
 			/* not needed for Consts */
-			if (!IsA(expr, Const))
+			if (lc2 != NULL)
 			{
-				int			stateidx = PruneCxtStateIdx(partnatts,
-														step->step.step_id,
-														keyno);
+				Expr *expr = lfirst(lc2);
 
-				/*
-				 * When planstate is NULL, pruning_steps is known not to
-				 * contain any expressions that depend on the parent plan.
-				 * Information of any available EXTERN parameters must be
-				 * passed explicitly in that case, which the caller must have
-				 * made available via econtext.
-				 */
-				if (planstate == NULL)
-					context->exprstates[stateidx] =
-						ExecInitExprWithParams(expr,
-											   econtext->ecxt_param_list_info);
-				else
-					context->exprstates[stateidx] =
-						ExecInitExpr(expr, context->planstate);
+				if (!IsA(expr, Const))
+				{
+					int			stateidx = PruneCxtStateIdx(partnatts,
+															step->step.step_id,
+															keyno);
+
+					/*
+					 * When planstate is NULL, pruning_steps is known not to
+					 * contain any expressions that depend on the parent plan.
+					 * Information of any available EXTERN parameters must be
+					 * passed explicitly in that case, which the caller must have
+					 * made available via econtext.
+					 */
+					if (planstate == NULL)
+						context->exprstates[stateidx] =
+							ExecInitExprWithParams(expr,
+												   econtext->ecxt_param_list_info);
+					else
+						context->exprstates[stateidx] =
+							ExecInitExpr(expr, context->planstate);
+				}
+				lc2 = lnext(step->exprs, lc2);
 			}
-			keyno++;
 		}
 	}
 }
diff --git a/src/test/regress/expected/partition_prune.out b/src/test/regress/expected/partition_prune.out
index bb1223e2b1..36791293ee 100644
--- a/src/test/regress/expected/partition_prune.out
+++ b/src/test/regress/expected/partition_prune.out
@@ -1921,6 +1921,19 @@ explain (costs off) select * from hp where (a = 1 and b = 'abcde') or (a = 2 and
          Filter: (((a = 1) AND (b = 'abcde'::text)) OR ((a = 2) AND (b = 'xxx'::text)) OR ((a IS NULL) AND (b IS NULL)))
 (7 rows)
 
+-- test run-time pruning
+set plan_cache_mode = 'force_generic_plan';
+prepare stmt (text) AS select * from hp where a is null and b = $1;
+explain (costs off) execute stmt('xxx');
+                 QUERY PLAN                 
+--------------------------------------------
+ Append
+   Subplans Removed: 3
+   ->  Seq Scan on hp2 hp_1
+         Filter: ((a IS NULL) AND (b = $1))
+(4 rows)
+
+deallocate stmt;
 -- test pruning when not all the partitions exist
 drop table hp1;
 drop table hp3;
diff --git a/src/test/regress/sql/partition_prune.sql b/src/test/regress/sql/partition_prune.sql
index 83fed54b8c..d23133fe43 100644
--- a/src/test/regress/sql/partition_prune.sql
+++ b/src/test/regress/sql/partition_prune.sql
@@ -374,6 +374,12 @@ explain (costs off) select * from hp where a = 2 and b = 'xxx';
 explain (costs off) select * from hp where a = 1 and b = 'abcde';
 explain (costs off) select * from hp where (a = 1 and b = 'abcde') or (a = 2 and b = 'xxx') or (a is null and b is null);
 
+-- test run-time pruning
+set plan_cache_mode = 'force_generic_plan';
+prepare stmt (text) AS select * from hp where a is null and b = $1;
+explain (costs off) execute stmt('xxx');
+deallocate stmt;
+
 -- test pruning when not all the partitions exist
 drop table hp1;
 drop table hp3;