planner: support limit_to_cop, agg_to_cop, ordered_index, no_ordered_index for quick binding

executor/adapter.go

@@ -1757,7 +1757,7 @@ func getEncodedPlan(stmtCtx *stmtctx.StatementContext, genHint bool) (encodedPla
 			switch tableHint.HintName.L {
 			case "memory_quota", "use_toja", "no_index_merge", "max_execution_time",
 				plannercore.HintAggToCop, plannercore.HintIgnoreIndex,
-				plannercore.HintReadFromStorage, plannercore.HintLimitToCop:
+				plannercore.HintReadFromStorage:
 				hints = append(hints, tableHint)
 			}
 		}

infoschema/test/clustertablestest/cluster_tables_test.go

@@ -931,6 +931,12 @@ func TestQuickBinding(t *testing.T) {
 		// 2-way merge joins
 		{`select /*+ merge_join(t1, t2), use_index(t1), use_index(t2) */ t1.* from t1, t2 where t1.a=t2.a and t1.a<?`, "merge_join(@`sel_1` `test`.`t1`), use_index(@`sel_1` `test`.`t1` ), use_index(@`sel_1` `test`.`t2` )", nil},
 		{`select /*+ merge_join(t1, t2), use_index(t1, k_a), use_index(t2, k_a) */ t1.* from t1, t2 where t1.a=t2.a and t1.a<?`, "merge_join(@`sel_1` `test`.`t1`), use_index(@`sel_1` `test`.`t1` `k_a`), use_index(@`sel_1` `test`.`t2` `k_a`)", nil},
+
+		// limit_to_cop
+		{`select /*+ limit_to_cop(), use_index(t1, k_a) */ * from t1 where a < ? limit 100`, "use_index(@`sel_1` `test`.`t1` `k_a`), limit_to_cop(@`sel_1`)", nil},
+		{`select /*+ limit_to_cop(), use_index(t1, k_a) */ * from t1 where b < ? limit 100`, "use_index(@`sel_1` `test`.`t1` `k_a`), limit_to_cop(@`sel_1`)", nil},
+		{`select /*+ limit_to_cop(), use_index(t1, k_a) */ * from t1 where a < ? order by a limit 100`, "use_index(@`sel_1` `test`.`t1` `k_a`), limit_to_cop(@`sel_1`)", nil},
+		{`select /*+ limit_to_cop(), use_index(t1, k_a) */ * from t1 where a < ? order by b limit 100`, "use_index(@`sel_1` `test`.`t1` `k_a`), limit_to_cop(@`sel_1`)", nil},
 	}
 
 	removeHint := func(sql string) string {

planner/core/hints.go

@@ -40,19 +40,16 @@ func GenHintsFromFlatPlan(flat *FlatPhysicalPlan) []*ast.TableOptimizerHint {
 		return nil
 	}
 	for _, op := range selectPlan {
-		if !op.IsRoot {
-			continue
-		}
 		p := op.Origin.(PhysicalPlan)
-		hints = genHintsFromSingle(p, nodeTp, hints)
+		hints = genHintsFromSingle(p, nodeTp, op.StoreType, hints)
 	}
 	for _, cte := range flat.CTEs {
 		for i, op := range cte {
 			if i == 0 || !op.IsRoot {
 				continue
 			}
 			p := op.Origin.(PhysicalPlan)
-			hints = genHintsFromSingle(p, nodeTp, hints)
+			hints = genHintsFromSingle(p, nodeTp, op.StoreType, hints)
 		}
 	}
 	return hints
@@ -164,15 +161,22 @@ func genHintsFromPhysicalPlan(p PhysicalPlan, nodeType utilhint.NodeType) (res [
 		res = append(res, genHintsFromPhysicalPlan(phCte.CTE.recursivePartPhysicalPlan, nodeType)...)
 	}
 
-	return genHintsFromSingle(p, nodeType, res)
+	return genHintsFromSingle(p, nodeType, kv.TiDB, res)
 }
 
-func genHintsFromSingle(p PhysicalPlan, nodeType utilhint.NodeType, res []*ast.TableOptimizerHint) []*ast.TableOptimizerHint {
+func genHintsFromSingle(p PhysicalPlan, nodeType utilhint.NodeType, storeType kv.StoreType, res []*ast.TableOptimizerHint) []*ast.TableOptimizerHint {
 	qbName, err := utilhint.GenerateQBName(nodeType, p.SelectBlockOffset())
 	if err != nil {
 		return res
 	}
 	switch pp := p.(type) {
+	case *PhysicalLimit, *PhysicalTopN:
+		if storeType == kv.TiKV {
+			res = append(res, &ast.TableOptimizerHint{
+				QBName:   qbName,
+				HintName: model.NewCIStr(HintLimitToCop),
+			})
+		}
 	case *PhysicalTableReader:
 		tbl, ok := pp.TablePlans[0].(*PhysicalTableScan)
 		if !ok {