Fix bug with explain and Add more message about join type.

src/backend/commands/explain.c

@@ -2296,8 +2296,9 @@ ExplainNode(PlanState *planstate, List *ancestors,
 			/* fall through to print additional fields the same as SeqScan */
 			/* FALLTHROUGH */
 		case T_SeqScan:
-			show_pushdown_runtime_filter_info("Rows Removed by Pushdown Runtime Filter",
-											  planstate, es);
+			if (IsA(planstate, SeqScanState))
+				show_pushdown_runtime_filter_info("Rows Removed by Pushdown Runtime Filter",
+												  planstate, es);
 			/* FALLTHROUGH */
 		case T_ValuesScan:
 		case T_CteScan:

src/backend/executor/nodeHashjoin.c

@@ -2195,13 +2195,19 @@ CreateRuntimeFilter(HashJoinState* hjstate)
 	List		*targets;
 
 	/*
-	 * Only applicatable for inner, right and semi join,
+	 * A build-side Bloom filter tells us if a row is definitely not in the build
+	 * side. This allows us to early-eliminate rows or early-accept rows depending
+	 * on the type of join.
+	 * Left Outer Join and Full Outer Join output all rows, so a build-side Bloom
+	 * filter would only allow us to early-output. Left Antijoin outputs only if
+	 * there is no match, so again early output. We don't implement early output
+	 * for now.
+	 * So it's only applicatable for inner, right and semi join.
 	 */
 	jointype = hjstate->js.jointype;
-	if (jointype != JOIN_INNER
-		&& jointype != JOIN_RIGHT
-		&& jointype != JOIN_SEMI
-	   )
+	if (jointype != JOIN_INNER &&
+		jointype != JOIN_RIGHT &&
+		jointype != JOIN_SEMI)
 		return;
 
 	hstate = castNode(HashState, innerPlanState(hjstate));

src/test/regress/expected/gp_runtime_filter.out

@@ -361,6 +361,25 @@ SELECT * FROM t1, t2 WHERE t1.c2 = t2.c2;
 RESET gp_enable_runtime_filter_pushdown;
 DROP TABLE IF EXISTS t1;
 DROP TABLE IF EXISTS t2;
+-- case3: bug fix with explain
+DROP TABLE IF EXISTS test_tablesample;
+NOTICE:  table "test_tablesample" does not exist, skipping
+CREATE TABLE test_tablesample (dist int, id int, name text) WITH (fillfactor=10) DISTRIBUTED BY (dist);
+INSERT INTO test_tablesample SELECT 0, i, repeat(i::text, 875) FROM generate_series(0, 9) s(i) ORDER BY i;
+INSERT INTO test_tablesample SELECT 3, i, repeat(i::text, 875) FROM generate_series(10, 19) s(i) ORDER BY i;
+INSERT INTO test_tablesample SELECT 5, i, repeat(i::text, 875) FROM generate_series(20, 29) s(i) ORDER BY i;
+SET gp_enable_runtime_filter_pushdown TO on;
+EXPLAIN (COSTS OFF) SELECT id FROM test_tablesample TABLESAMPLE SYSTEM (50) REPEATABLE (2);
+                                QUERY PLAN                                
+--------------------------------------------------------------------------
+ Gather Motion 3:1  (slice1; segments: 3)
+   ->  Sample Scan on test_tablesample
+         Sampling: system ('50'::real) REPEATABLE ('2'::double precision)
+ Optimizer: Postgres query optimizer
+(4 rows)
+
+RESET gp_enable_runtime_filter_pushdown;
+DROP TABLE IF EXISTS test_tablesample;
 -- Clean up: reset guc
 SET gp_enable_runtime_filter TO off;
 SET optimizer TO default;

src/test/regress/sql/gp_runtime_filter.sql

@@ -136,6 +136,19 @@ RESET gp_enable_runtime_filter_pushdown;
 DROP TABLE IF EXISTS t1;
 DROP TABLE IF EXISTS t2;
 
+-- case3: bug fix with explain
+DROP TABLE IF EXISTS test_tablesample;
+CREATE TABLE test_tablesample (dist int, id int, name text) WITH (fillfactor=10) DISTRIBUTED BY (dist);
+INSERT INTO test_tablesample SELECT 0, i, repeat(i::text, 875) FROM generate_series(0, 9) s(i) ORDER BY i;
+INSERT INTO test_tablesample SELECT 3, i, repeat(i::text, 875) FROM generate_series(10, 19) s(i) ORDER BY i;
+INSERT INTO test_tablesample SELECT 5, i, repeat(i::text, 875) FROM generate_series(20, 29) s(i) ORDER BY i;
+
+SET gp_enable_runtime_filter_pushdown TO on;
+EXPLAIN (COSTS OFF) SELECT id FROM test_tablesample TABLESAMPLE SYSTEM (50) REPEATABLE (2);
+RESET gp_enable_runtime_filter_pushdown;
+
+DROP TABLE IF EXISTS test_tablesample;
+
 -- Clean up: reset guc
 SET gp_enable_runtime_filter TO off;
 SET optimizer TO default;