From 1d304c75b3f2da9511a7b0e1af9377b39b13883c Mon Sep 17 00:00:00 2001
From: Weizhen Wang <wangweizhen@pingcap.com>
Date: Thu, 4 Jul 2024 23:48:05 +0800
Subject: [PATCH] u

Signed-off-by: Weizhen Wang <wangweizhen@pingcap.com>
---
 pkg/bindinfo/tests/bind_test.go    | 116 ++++++++++++++++++++++++++++-
 pkg/planner/core/find_best_task.go |   3 -
 2 files changed, 115 insertions(+), 4 deletions(-)

diff --git a/pkg/bindinfo/tests/bind_test.go b/pkg/bindinfo/tests/bind_test.go
index 66ddefe3733f5..f6f47763dafd2 100644
--- a/pkg/bindinfo/tests/bind_test.go
+++ b/pkg/bindinfo/tests/bind_test.go
@@ -925,11 +925,125 @@ func testFuzzyBindingHints(t *testing.T) {
 		binding   string
 		qTemplate string
 	}{
+		// use index
+		{`create global binding using select /*+ use_index(t1, c) */ * from *.t1 where a=1`,
+			`select * from %st1 where a=1000`},
+		{`create global binding using select /*+ use_index(t1, c) */ * from *.t1 where d<1`,
+			`select * from %st1 where d<10000`},
+		{`create global binding using select /*+ use_index(t1, c) */ * from *.t1, *.t2 where t1.d<1`,
+			`select * from %st1, t2 where t1.d<100`},
+		{`create global binding using select /*+ use_index(t1, c) */ * from *.t1, *.t2 where t1.d<1`,
+			`select * from t1, %st2 where t1.d<100`},
+		{`create global binding using select /*+ use_index(t1, c), use_index(t2, a) */ * from *.t1, *.t2 where t1.d<1`,
+			`select * from %st1, t2 where t1.d<100`},
+		{`create global binding using select /*+ use_index(t1, c), use_index(t2, a) */ * from *.t1, *.t2 where t1.d<1`,
+			`select * from t1, %st2 where t1.d<100`},
+		{`create global binding using select /*+ use_index(t1, c), use_index(t2, a) */ * from *.t1, *.t2, *.t3 where t1.d<1`,
+			`select * from %st1, t2, t3 where t1.d<100`},
+		{`create global binding using select /*+ use_index(t1, c), use_index(t2, a) */ * from *.t1, *.t2, *.t3 where t1.d<1`,
+			`select * from t1, t2, %st3 where t1.d<100`},
 
-		// join type hint
+		// ignore index
+		{`create global binding using select /*+ ignore_index(t1, b) */ * from *.t1 where b=1`,
+			`select * from %st1 where b=1000`},
+		{`create global binding using select /*+ ignore_index(t1, b) */ * from *.t1 where b>1`,
+			`select * from %st1 where b>1000`},
+		{`create global binding using select /*+ ignore_index(t1, b) */ * from *.t1 where b in (1,2)`,
+			`select * from %st1 where b in (1)`},
+		{`create global binding using select /*+ ignore_index(t1, b) */ * from *.t1 where b in (1,2)`,
+			`select * from %st1 where b in (1,2,3,4,5)`},
 
+		// order index hint
+		{`create global binding using select /*+ order_index(t1, a) */ a from *.t1 where a<10 order by a limit 10`,
+			`select a from %st1 where a<10000 order by a limit 10`},
+		{`create global binding using select /*+ order_index(t1, b) */ b from *.t1 where b>10 order by b limit 1111`,
+			`select b from %st1 where b>2 order by b limit 10`},
+
+		// no order index hint
+		{`create global binding using select /*+ no_order_index(t1, c) */ c from *.t1 where c<10 order by c limit 10`,
+			`select c from %st1 where c<10000 order by c limit 10`},
+		{`create global binding using select /*+ no_order_index(t1, d) */ d from *.t1 where d>10 order by d limit 1111`,
+			`select d from %st1 where d>2 order by d limit 10`},
+
+		// agg hint
+		{`create global binding using select /*+ hash_agg() */ count(*) from *.t1 group by a`,
+			`select count(*) from %st1 group by a`},
+		{`create global binding using select /*+ stream_agg() */ count(*) from *.t1 group by b`,
+			`select count(*) from %st1 group by b`},
+
+		// to_cop hint
+		{`create global binding using select /*+ agg_to_cop() */ sum(a) from *.t1`,
+			`select sum(a) from %st1`},
+		{`create global binding using select /*+ limit_to_cop() */ a from *.t1 limit 10`,
+			`select a from %st1 limit 101`},
+
+		// index merge hint
+		{`create global binding using select /*+ use_index_merge(t1, c, d) */ * from *.t1 where c=1 or d=1`,
+			`select * from %st1 where c=1000 or d=1000`},
+		{`create global binding using select /*+ no_index_merge() */ * from *.t1 where a=1 or b=1`,
+			`select * from %st1 where a=1000 or b=1000`},
+
+		// join type hint
+		{`create global binding using select /*+ hash_join(t1) */ * from *.t1, *.t2 where t1.a=t2.a`,
+			`select * from %st1, t2 where t1.a=t2.a`},
+		{`create global binding using select /*+ hash_join(t2) */ * from *.t1, *.t2 where t1.a=t2.a`,
+			`select * from t1, %st2 where t1.a=t2.a`},
+		{`create global binding using select /*+ hash_join(t2) */ * from *.t1, *.t2, *.t3 where t1.a=t2.a and t3.b=t2.b`,
+			`select * from t1, %st2, t3 where t1.a=t2.a and t3.b=t2.b`},
+		{`create global binding using select /*+ hash_join_build(t1) */ * from *.t1, *.t2 where t1.a=t2.a`,
+			`select * from t1, %st2 where t1.a=t2.a`},
+		{`create global binding using select /*+ hash_join_probe(t1) */ * from *.t1, *.t2 where t1.a=t2.a`,
+			`select * from t1, %st2 where t1.a=t2.a`},
+		{`create global binding using select /*+ merge_join(t1) */ * from *.t1, *.t2 where t1.a=t2.a`,
+			`select * from %st1, t2 where t1.a=t2.a`},
+		{`create global binding using select /*+ merge_join(t2) */ * from *.t1, *.t2 where t1.a=t2.a`,
+			`select * from t1, %st2 where t1.a=t2.a`},
+		{`create global binding using select /*+ merge_join(t2) */ * from *.t1, *.t2, *.t3 where t1.a=t2.a and t3.b=t2.b`,
+			`select * from t1, %st2, t3 where t1.a=t2.a and t3.b=t2.b`},
 		{`create global binding using select /*+ inl_join(t1) */ * from *.t1, *.t2 where t1.a=t2.a`,
 			`select * from %st1, t2 where t1.a=t2.a`},
+		{`create global binding using select /*+ inl_join(t2) */ * from *.t1, *.t2 where t1.a=t2.a`,
+			`select * from t1, %st2 where t1.a=t2.a`},
+		{`create global binding using select /*+ inl_join(t2) */ * from *.t1, *.t2, *.t3 where t1.a=t2.a and t3.b=t2.b`,
+			`select * from t1, %st2, t3 where t1.a=t2.a and t3.b=t2.b`},
+
+		// no join type hint
+		{`create global binding using select /*+ no_hash_join(t1) */ * from *.t1, *.t2 where t1.b=t2.b`,
+			`select * from %st1, t2 where t1.b=t2.b`},
+		{`create global binding using select /*+ no_hash_join(t2) */ * from *.t1, *.t2 where t1.c=t2.c`,
+			`select * from t1, %st2 where t1.c=t2.c`},
+		{`create global binding using select /*+ no_hash_join(t2) */ * from *.t1, *.t2, *.t3 where t1.a=t2.a and t3.b=t2.b`,
+			`select * from t1, %st2, t3 where t1.a=t2.a and t3.b=t2.b`},
+		{`create global binding using select /*+ no_merge_join(t1) */ * from *.t1, *.t2 where t1.b=t2.b`,
+			`select * from %st1, t2 where t1.b=t2.b`},
+		{`create global binding using select /*+ no_merge_join(t2) */ * from *.t1, *.t2 where t1.c=t2.c`,
+			`select * from t1, %st2 where t1.c=t2.c`},
+		{`create global binding using select /*+ no_merge_join(t2) */ * from *.t1, *.t2, *.t3 where t1.a=t2.a and t3.b=t2.b`,
+			`select * from t1, %st2, t3 where t1.a=t2.a and t3.b=t2.b`},
+		{`create global binding using select /*+ no_index_join(t1) */ * from *.t1, *.t2 where t1.b=t2.b`,
+			`select * from %st1, t2 where t1.b=t2.b`},
+		{`create global binding using select /*+ no_index_join(t2) */ * from *.t1, *.t2 where t1.c=t2.c`,
+			`select * from t1, %st2 where t1.c=t2.c`},
+		{`create global binding using select /*+ no_index_join(t2) */ * from *.t1, *.t2, *.t3 where t1.a=t2.a and t3.b=t2.b`,
+			`select * from t1, %st2, t3 where t1.a=t2.a and t3.b=t2.b`},
+
+		// join order hint
+		{`create global binding using select /*+ leading(t2) */ * from *.t1, *.t2 where t1.b=t2.b`,
+			`select * from %st1, t2 where t1.b=t2.b`},
+		{`create global binding using select /*+ leading(t2) */ * from *.t1, *.t2 where t1.c=t2.c`,
+			`select * from t1, %st2 where t1.c=t2.c`},
+		{`create global binding using select /*+ leading(t2, t1) */ * from *.t1, *.t2 where t1.c=t2.c`,
+			`select * from t1, %st2 where t1.c=t2.c`},
+		{`create global binding using select /*+ leading(t1, t2) */ * from *.t1, *.t2 where t1.c=t2.c`,
+			`select * from t1, %st2 where t1.c=t2.c`},
+		{`create global binding using select /*+ leading(t1) */ * from *.t1, *.t2, *.t3 where t1.a=t2.a and t3.b=t2.b`,
+			`select * from t1, %st2, t3 where t1.a=t2.a and t3.b=t2.b`},
+		{`create global binding using select /*+ leading(t2) */ * from *.t1, *.t2, *.t3 where t1.a=t2.a and t3.b=t2.b`,
+			`select * from t1, %st2, t3 where t1.a=t2.a and t3.b=t2.b`},
+		{`create global binding using select /*+ leading(t2,t3) */ * from *.t1, *.t2, *.t3 where t1.a=t2.a and t3.b=t2.b`,
+			`select * from t1, %st2, t3 where t1.a=t2.a and t3.b=t2.b`},
+		{`create global binding using select /*+ leading(t2,t3,t1) */ * from *.t1, *.t2, *.t3 where t1.a=t2.a and t3.b=t2.b`,
+			`select * from t1, %st2, t3 where t1.a=t2.a and t3.b=t2.b`},
 	} {
 		removeAllBindings(tk, true)
 		tk.MustExec(c.binding)
diff --git a/pkg/planner/core/find_best_task.go b/pkg/planner/core/find_best_task.go
index df2f386b88d2b..c4e384b541260 100644
--- a/pkg/planner/core/find_best_task.go
+++ b/pkg/planner/core/find_best_task.go
@@ -279,9 +279,6 @@ func iteratePhysicalPlan4BaseLogical(
 		if childTask != nil && childTask.Invalid() {
 			return nil, 0, childCnts, nil
 		}
-		if childTask == nil {
-			continue
-		}
 		childTasks = append(childTasks, childTask)
 	}
 	// This check makes sure that there is no invalid child task.