core: add the implemet of setparamtype at show, showddl, datasource, limit plan ; executor: add new case 'LogicalLimit' at Next()

executor/prepared.go

@@ -220,6 +220,8 @@ func (e *PrepareExec) Next(ctx context.Context, req *chunk.Chunk) error {
 		err = SetUpdateParamType(p.(*plannercore.Update), &prepared.Params)
 	case *plannercore.LogicalSort:
 		err = SetSortType(p.(*plannercore.LogicalSort), &prepared.Params)
+	case *plannercore.LogicalLimit:
+		err = SetLimitType(p.(*plannercore.LogicalLimit), &prepared.Params)
 	}
 	if err != nil {
 		return err
@@ -397,6 +399,11 @@ func SetSortType(sort *plannercore.LogicalSort, i *[]ast.ParamMarkerExpr) error
 	return sort.SetParamType(i)
 }
 
+// SetLimitType set the parameter type of limit plan
+func SetLimitType(limit *plannercore.LogicalLimit, i *[]ast.ParamMarkerExpr) error {
+	return limit.SetParamType(i)
+}
+
 // ExecuteExec represents an EXECUTE executor.
 // It cannot be executed by itself, all it needs to do is to build
 // another Executor from a prepared statement.

executor/prepared_test.go

@@ -348,3 +348,65 @@ func (s *testPrepareSuite) TestPlanCacheWithDifferentVariableTypes(c *C) {
 		}
 	}
 }
+
+type testParamType struct {
+	sql        string
+	expectType []byte
+	paramCount int
+}
+
+//
+func (s *testPrepareSuite) TestGetPrepareParamType(c *C) {
+	store, _, err := newStoreWithBootstrap()
+	c.Assert(err, IsNil)
+
+	se, err := session.CreateSession4Test(store)
+	c.Assert(err, IsNil)
+	tk := testkit.NewTestKit(c, store)
+	tk.Se = se
+
+	tk.Se.Auth(&auth.UserIdentity{Username: "root", Hostname: "localhost", CurrentUser: true, AuthUsername: "root", AuthHostname: "%"}, nil, []byte("012345678901234567890"))
+
+	sm := &mockSessionManager2{
+		se: se,
+	}
+	se.SetSessionManager(sm)
+
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists student")
+
+	tk.MustExec("create table student (id int primary key, name varchar(255), age int)")
+	tk.MustExec("insert into student values(1, \"zhangsan\", 18)")
+
+	sqlList := []*testParamType{
+		{
+			// limit and offset followed by parameters are constants,
+			// their kind be set to "0" by default.
+			sql:        "select * from student where name = $1 limit $2 offset 1",
+			paramCount: 2,
+			expectType: []byte{mysql.TypeVarchar, mysql.TypeDecimal},
+		}, {
+			// If limit and offset followed by parameters are ParamMakerExpr,
+			// TiDB-Server will generate a LogicalTableDual,
+			// We can't get any param type.
+			// todo get param type in this case.
+			sql:        "select * from student where name = $1 limit $2 offset $3",
+			paramCount: 3,
+			expectType: []byte{mysql.TypeDecimal, mysql.TypeDecimal, mysql.TypeDecimal},
+		},
+	}
+
+	for _, v1 := range sqlList {
+		stmtID, paramCount, _, err := tk.Se.PrepareStmt(v1.sql, "")
+		c.Assert(paramCount, Equals, v1.paramCount)
+		c.Assert(err, IsNil)
+
+		if cachedStmt, ok := tk.Se.GetSessionVars().PreparedStmts[stmtID].(*plannercore.CachedPrepareStmt); ok {
+			cachedParams := cachedStmt.PreparedAst.Params
+			for i, _ := range cachedParams {
+				paramType := cachedParams[i].GetType().Tp
+				c.Assert(paramType, Equals, v1.expectType[i])
+			}
+		}
+	}
+}

planner/core/logical_plans.go

@@ -611,7 +611,8 @@ type DataSource struct {
 	isForUpdateRead bool
 }
 
-// SetParamType todo 设置参数类型
+// SetParamType set the parameter type of dataSource plan
+// dataSource plan is always the last node of o plan tree and it will not contain any parameter.Just return nil
 func (ds *DataSource) SetParamType(paramExprs *[]ast.ParamMarkerExpr) (err error) {
 	return err
 }
@@ -1098,8 +1099,17 @@ type LogicalLimit struct {
 	limitHints limitHintInfo
 }
 
-// SetParamType todo 设置参数类型
-func (p *LogicalLimit) SetParamType(paramExprs *[]ast.ParamMarkerExpr) (err error) {
+// SetParamType set the parameter type of logicalLimit plan
+// when send "limit $1 offset $2",planbuilder will convert it to a tableDual plan.see why at /planner/core/logical_plan_builder.go buildLimit
+func (ll *LogicalLimit) SetParamType(paramExprs *[]ast.ParamMarkerExpr) (err error) {
+	if childs := ll.children; childs != nil {
+		for _, child := range childs {
+			err = child.SetParamType(paramExprs)
+			if err != nil {
+				return err
+			}
+		}
+	}
 	return err
 }
 
@@ -1240,7 +1250,11 @@ type LogicalShow struct {
 	ShowContents
 }
 
-// SetParamType todo 设置参数类型
+// SetParamType set the parameter type of logicalShow plan
+// https://www.postgresql.org/docs/current/sql-show.html
+// According to the postgresql document, any parameter won't follow the show statement.
+// Besides, show statement won't be the sub statement of any other sql statement.
+// So, Show statement doesn't need actual implement. Just return nil.
 func (p *LogicalShow) SetParamType(paramExprs *[]ast.ParamMarkerExpr) (err error) {
 	return err
 }
@@ -1252,7 +1266,10 @@ type LogicalShowDDLJobs struct {
 	JobNumber int64
 }
 
-// SetParamType todo 设置参数类型
+// SetParamType set the parameter type of logicalShowDDLJobs plan
+// https://www.postgresql.org/docs/current/sql-show.html
+// Actually, postgresql doesn't support the syntax like "show create table tname"
+// And showddl statement won't contain parameter. Just return nil
 func (p *LogicalShowDDLJobs) SetParamType(paramExprs *[]ast.ParamMarkerExpr) (err error) {
 	return err
 }

planner/core/physical_plans.go

@@ -916,8 +916,11 @@ type PhysicalShow struct {
 	ShowContents
 }
 
-// SetParamType set the parameter type in ParamMarkerExpr from PhysicalShow
-// todo 从PhysicalShow计划中获取参数类型
+// SetParamType set the parameter type of physicalShow plan
+// https://www.postgresql.org/docs/current/sql-show.html
+// According to the postgresql document, any parameter won't follow the show statement.
+// Besides, show statement won't be the sub statement of any other sql statement.
+// So, Show statement doesn't need actual implement. Just return nil.
 func (show *PhysicalShow) SetParamType(paramExprs *[]ast.ParamMarkerExpr) (err error) {
 	return err
 }
@@ -929,8 +932,10 @@ type PhysicalShowDDLJobs struct {
 	JobNumber int64
 }
 
-// SetParamType set the parameter type in ParamMarkerExpr from PhysicalShowDDLJobs
-// todo 从PhysicalShowDDLJobs中获取参数类型
+// SetParamType set the parameter type of physicalShowDDLJobs plan
+// https://www.postgresql.org/docs/current/sql-show.html
+// Actually, postgresql doesn't support the syntax like "show create table tname"
+// And showddl statement won't contain parameter. Just return nil
 func (ddl *PhysicalShowDDLJobs) SetParamType(paramExprs *[]ast.ParamMarkerExpr) (err error) {
 	return err
 }