executor: set the correct stmtCtx for explain statement (pingcap#11186)

executor/executor.go

@@ -1346,13 +1346,19 @@ func ResetContextOfStmt(ctx sessionctx.Context, s ast.StmtNode) (err error) {
 	default:
 		sc.MemTracker.SetActionOnExceed(&memory.LogOnExceed{})
 	}
-
 	if execStmt, ok := s.(*ast.ExecuteStmt); ok {
 		s, err = getPreparedStmt(execStmt, vars)
 		if err != nil {
 			return
 		}
 	}
+	// execute missed stmtID uses empty sql
+	sc.OriginalSQL = s.Text()
+	if explainStmt, ok := s.(*ast.ExplainStmt); ok {
+		sc.InExplainStmt = true
+		sc.CastStrToIntStrict = true
+		s = explainStmt.Stmt
+	}
 	// TODO: Many same bool variables here.
 	// We should set only two variables (
 	// IgnoreErr and StrictSQLMode) to avoid setting the same bool variables and

executor/explainfor_test.go

@@ -0,0 +1,101 @@
+// Copyright 2019 PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package executor_test
+
+import (
+	"fmt"
+
+	. "github.com/pingcap/check"
+	"github.com/pingcap/parser/auth"
+	"github.com/pingcap/tidb/planner/core"
+	"github.com/pingcap/tidb/util"
+	"github.com/pingcap/tidb/util/testkit"
+)
+
+// mockSessionManager is a mocked session manager which is used for test.
+type mockSessionManager1 struct {
+	PS []*util.ProcessInfo
+}
+
+// ShowProcessList implements the SessionManager.ShowProcessList interface.
+func (msm *mockSessionManager1) ShowProcessList() map[uint64]*util.ProcessInfo {
+	ret := make(map[uint64]*util.ProcessInfo)
+	for _, item := range msm.PS {
+		ret[item.ID] = item
+	}
+	return ret
+}
+
+func (msm *mockSessionManager1) GetProcessInfo(id uint64) (*util.ProcessInfo, bool) {
+	for _, item := range msm.PS {
+		if item.ID == id {
+			return item, true
+		}
+	}
+	return &util.ProcessInfo{}, false
+}
+
+// Kill implements the SessionManager.Kill interface.
+func (msm *mockSessionManager1) Kill(cid uint64, query bool) {
+
+}
+
+func (s *testSuite) TestExplainFor(c *C) {
+	tkRoot := testkit.NewTestKitWithInit(c, s.store)
+	tkUser := testkit.NewTestKitWithInit(c, s.store)
+	tkRoot.MustExec("create table t1(c1 int, c2 int)")
+	tkRoot.MustExec("create table t2(c1 int, c2 int)")
+	tkRoot.MustExec("create user tu@'%'")
+	tkRoot.Se.Auth(&auth.UserIdentity{Username: "root", Hostname: "localhost", CurrentUser: true, AuthUsername: "root", AuthHostname: "%"}, nil, []byte("012345678901234567890"))
+	tkUser.Se.Auth(&auth.UserIdentity{Username: "tu", Hostname: "localhost", CurrentUser: true, AuthUsername: "tu", AuthHostname: "%"}, nil, []byte("012345678901234567890"))
+
+	tkRoot.MustQuery("select * from t1;")
+	tkRootProcess := tkRoot.Se.ShowProcess()
+	ps := []*util.ProcessInfo{tkRootProcess}
+	tkRoot.Se.SetSessionManager(&mockSessionManager1{PS: ps})
+	tkUser.Se.SetSessionManager(&mockSessionManager1{PS: ps})
+	tkRoot.MustQuery(fmt.Sprintf("explain for connection %d", tkRootProcess.ID)).Check(testkit.Rows(
+		"TableReader_5 10000.00 root data:TableScan_4",
+		"└─TableScan_4 10000.00 cop table:t1, range:[-inf,+inf], keep order:false, stats:pseudo",
+	))
+	err := tkUser.ExecToErr(fmt.Sprintf("explain for connection %d", tkRootProcess.ID))
+	c.Check(core.ErrAccessDenied.Equal(err), IsTrue)
+	err = tkUser.ExecToErr("explain for connection 42")
+	c.Check(core.ErrNoSuchThread.Equal(err), IsTrue)
+
+	tkRootProcess.Plan = nil
+	ps = []*util.ProcessInfo{tkRootProcess}
+	tkRoot.Se.SetSessionManager(&mockSessionManager1{PS: ps})
+	tkRoot.MustExec(fmt.Sprintf("explain for connection %d", tkRootProcess.ID))
+}
+
+func (s *testSuite) TestIssue11124(c *C) {
+	tk := testkit.NewTestKitWithInit(c, s.store)
+	tk2 := testkit.NewTestKitWithInit(c, s.store)
+	tk.MustExec("create table kankan1(id int, name text);")
+	tk.MustExec("create table kankan2(id int, h1 text);")
+	tk.MustExec("insert into kankan1 values(1, 'a'), (2, 'a');")
+	tk.MustExec("insert into kankan2 values(2, 'z');")
+	tk.MustQuery("select t1.id from kankan1 t1 left join kankan2 t2 on t1.id = t2.id where (case  when t1.name='b' then 'case2' when t1.name='a' then 'case1' else NULL end) = 'case1'")
+	tkRootProcess := tk.Se.ShowProcess()
+	ps := []*util.ProcessInfo{tkRootProcess}
+	tk.Se.SetSessionManager(&mockSessionManager1{PS: ps})
+	tk2.Se.SetSessionManager(&mockSessionManager1{PS: ps})
+
+	rs := tk.MustQuery("explain select t1.id from kankan1 t1 left join kankan2 t2 on t1.id = t2.id where (case  when t1.name='b' then 'case2' when t1.name='a' then 'case1' else NULL end) = 'case1'").Rows()
+	rs2 := tk2.MustQuery(fmt.Sprintf("explain for connection %d", tkRootProcess.ID)).Rows()
+	for i := range rs {
+		c.Assert(rs[i], DeepEquals, rs2[i])
+	}
+}

executor/point_get_test.go

@@ -176,7 +176,7 @@ func (s *testPointGetSuite) TestIndexLookupCharPK(c *C) {
 	// Test truncate with sql mode `PAD_CHAR_TO_FULL_LENGTH`.
 	tk.MustExec(`set @@sql_mode="PAD_CHAR_TO_FULL_LENGTH";`)
 	tk.MustIndexLookup(`select * from t tmp where a = "aa";`).Check(testkit.Rows(`aa bb`))
-	tk.MustIndexLookup(`select * from t tmp where a = "aab";`).Check(testkit.Rows())
+	tk.MustTableDual(`select * from t tmp where a = "aab";`).Check(testkit.Rows())
 
 	tk.MustExec(`truncate table t;`)
 	tk.MustExec(`insert into t values("a ", "b ");`)
@@ -189,9 +189,9 @@ func (s *testPointGetSuite) TestIndexLookupCharPK(c *C) {
 
 	// Test trailing spaces with sql mode `PAD_CHAR_TO_FULL_LENGTH`.
 	tk.MustExec(`set @@sql_mode="PAD_CHAR_TO_FULL_LENGTH";`)
-	tk.MustIndexLookup(`select * from t tmp where a = "a";`).Check(testkit.Rows())
+	tk.MustTableDual(`select * from t tmp where a = "a";`).Check(testkit.Rows())
 	tk.MustIndexLookup(`select * from t tmp where a = "a ";`).Check(testkit.Rows(`a b`))
-	tk.MustIndexLookup(`select * from t tmp where a = "a  ";`).Check(testkit.Rows())
+	tk.MustTableDual(`select * from t tmp where a = "a  ";`).Check(testkit.Rows())
 
 	// Test CHAR BINARY.
 	tk.MustExec(`drop table if exists t;`)

util/testkit/testkit.go

@@ -185,6 +185,20 @@ func (tk *TestKit) MustIndexLookup(sql string, args ...interface{}) *Result {
 	return tk.MustQuery(sql, args...)
 }
 
+// MustTableDual checks whether the plan for the sql is TableDual.
+func (tk *TestKit) MustTableDual(sql string, args ...interface{}) *Result {
+	rs := tk.MustQuery("explain "+sql, args...)
+	hasTableDual := false
+	for i := range rs.rows {
+		if strings.Contains(rs.rows[i][0], "TableDual") {
+			hasTableDual = true
+			break
+		}
+	}
+	tk.c.Assert(hasTableDual, check.IsTrue)
+	return tk.MustQuery(sql, args...)
+}
+
 // MustPointGet checks whether the plan for the sql is Point_Get.
 func (tk *TestKit) MustPointGet(sql string, args ...interface{}) *Result {
 	rs := tk.MustQuery("explain "+sql, args...)