diff --git a/src/test/modules/test_bitmapset/expected/test_bitmapset.out b/src/test/modules/test_bitmapset/expected/test_bitmapset.out
index 106898d09d5..f8f5cf5e7f0 100644
--- a/src/test/modules/test_bitmapset/expected/test_bitmapset.out
+++ b/src/test/modules/test_bitmapset/expected/test_bitmapset.out
@@ -1643,7 +1643,7 @@ SELECT test_bms_nonempty_difference('(b 1 2)', '(b 50 100)') AS result;
 (1 row)
 
 -- random operations
-SELECT test_random_operations(NULL, 10000, 81920, 0) > 0 AS result;
+SELECT test_random_operations(NULL, 10000, 0, 81920) > 0 AS result;
  result 
 --------
  t
diff --git a/src/test/modules/test_bitmapset/sql/test_bitmapset.sql b/src/test/modules/test_bitmapset/sql/test_bitmapset.sql
index 67ad57cf956..d44cda114a4 100644
--- a/src/test/modules/test_bitmapset/sql/test_bitmapset.sql
+++ b/src/test/modules/test_bitmapset/sql/test_bitmapset.sql
@@ -421,7 +421,7 @@ SELECT test_bms_nonempty_difference('(b 100)', '(b 5)') AS result;
 SELECT test_bms_nonempty_difference('(b 1 2)', '(b 50 100)') AS result;
 
 -- random operations
-SELECT test_random_operations(NULL, 10000, 81920, 0) > 0 AS result;
+SELECT test_random_operations(NULL, 10000, 0, 81920) > 0 AS result;
 
 -- perform some random tests on bms_offset_members()
 SELECT test_random_offset_operations(NULL, 1000, 0, 1024) AS result;
diff --git a/src/test/modules/test_bitmapset/test_bitmapset.c b/src/test/modules/test_bitmapset/test_bitmapset.c
index f7de9e7757e..af8c664949e 100644
--- a/src/test/modules/test_bitmapset/test_bitmapset.c
+++ b/src/test/modules/test_bitmapset/test_bitmapset.c
@@ -598,10 +598,11 @@ test_bitmap_match(PG_FUNCTION_ARGS)
  * equivalent C functions, this stresses Bitmapsets in a random fashion for
  * various operations.
  *
- * "min_value" is the minimal value used for the members, that will stand
- * up to a range of "max_range".  "num_ops" defines the number of time each
- * operation is done.  "seed" is a random seed used to calculate the member
- * values.  When "seed" is NULL, a random seed will be chosen automatically.
+ * Arguments:
+ *  arg1: optional random seed.  NULL autoselects the seed.
+ *  arg2: defines the number of times each operation is done.
+ *  arg3: the minimum bitmapset member number to use in the random set.
+ *  arg4: the maximum bitmapset member number to use in the random set.
  *
  * The return value is the number of times all operations have been executed.
  */
@@ -615,9 +616,10 @@ test_random_operations(PG_FUNCTION_ARGS)
 	pg_prng_state state;
 	uint64		seed = GetCurrentTimestamp();
 	int			num_ops;
-	int			max_range;
 	int			min_value;
+	int			max_value;
 	int			member;
+	uint32		range;
 	int		   *members;
 	int			num_members = 0;
 	int			total_ops = 0;
@@ -625,18 +627,22 @@ test_random_operations(PG_FUNCTION_ARGS)
 	if (!PG_ARGISNULL(0))
 		seed = PG_GETARG_INT64(0);
 
-	num_ops = PG_GETARG_INT32(1);
-	max_range = PG_GETARG_INT32(2);
-	min_value = PG_GETARG_INT32(3);
-
-	if (PG_ARGISNULL(1) || num_ops <= 0)
+	if (PG_ARGISNULL(1) || PG_GETARG_INT32(1) <= 0)
 		elog(ERROR, "invalid number of operations");
-	if (PG_ARGISNULL(2) || max_range <= 0)
-		elog(ERROR, "invalid maximum range");
-	if (PG_ARGISNULL(3) || min_value < 0)
+	if (PG_ARGISNULL(2) || PG_GETARG_INT32(2) < 0)
 		elog(ERROR, "invalid minimum value");
+	if (PG_ARGISNULL(3) || PG_GETARG_INT32(3) < 0)
+		elog(ERROR, "invalid maximum value");
+
+	num_ops = PG_GETARG_INT32(1);
+	min_value = PG_GETARG_INT32(2);
+	max_value = PG_GETARG_INT32(3);
+
+	if (max_value < min_value)
+		elog(ERROR, "maximum value must be greater than or equal to minimum value");
 
 	pg_prng_seed(&state, seed);
+	range = (uint32) max_value - (uint32) min_value + 1;
 
 	/*
 	 * There can be up to "num_ops" members added.  This is very unlikely,
@@ -650,7 +656,7 @@ test_random_operations(PG_FUNCTION_ARGS)
 	{
 		CHECK_FOR_INTERRUPTS();
 
-		member = pg_prng_uint32(&state) % max_range + min_value;
+		member = min_value + (pg_prng_uint32(&state) % range);
 
 		if (!bms_is_member(member, bms1))
 			members[num_members++] = member;
@@ -662,7 +668,7 @@ test_random_operations(PG_FUNCTION_ARGS)
 	{
 		CHECK_FOR_INTERRUPTS();
 
-		member = pg_prng_uint32(&state) % max_range + min_value;
+		member = min_value + (pg_prng_uint32(&state) % range);
 
 		if (!bms_is_member(member, bms2))
 			members[num_members++] = member;
@@ -737,7 +743,7 @@ test_random_operations(PG_FUNCTION_ARGS)
 		switch (pg_prng_uint32(&state) % 3)
 		{
 			case 0:				/* add */
-				member = pg_prng_uint32(&state) % max_range + min_value;
+				member = min_value + (pg_prng_uint32(&state) % range);
 				if (!bms_is_member(member, bms))
 					members[num_members++] = member;
 				bms = bms_add_member(bms, member);