[hotfix]: cherry-pick 33946, 34538 and 35367 to v5.2.4

executor/infoschema_reader.go

@@ -57,6 +57,7 @@ import (
 	"github.com/pingcap/tidb/util/chunk"
 	"github.com/pingcap/tidb/util/collate"
 	"github.com/pingcap/tidb/util/deadlockhistory"
+	"github.com/pingcap/tidb/util/hint"
 	"github.com/pingcap/tidb/util/keydecoder"
 	"github.com/pingcap/tidb/util/logutil"
 	"github.com/pingcap/tidb/util/pdapi"
@@ -615,85 +616,119 @@ func (e *hugeMemTableRetriever) dataForColumnsInTable(ctx context.Context, sctx
 		sctx.GetSessionVars().StmtCtx.AppendWarning(err)
 		return
 	}
+	is := sctx.GetInfoSchema().(infoschema.InfoSchema)
+	var viewSchema *expression.Schema
+	var viewOutputNames types.NameSlice
+	if tbl.IsView() {
+		var viewLogicalPlan plannercore.Plan
+		// Build plan is not thread safe, there will be concurrency on sessionctx.
+		if err := runWithSystemSession(sctx, func(s sessionctx.Context) error {
+			planBuilder, _ := plannercore.NewPlanBuilder().Init(s, is, &hint.BlockHintProcessor{})
+			var err error
+			viewLogicalPlan, err = planBuilder.BuildDataSourceFromView(ctx, schema.Name, tbl)
+			if err != nil {
+				return errors.Trace(err)
+			}
+			return nil
+		}); err != nil {
+			sctx.GetSessionVars().StmtCtx.AppendWarning(err)
+			return
+		}
+
+		viewSchema = viewLogicalPlan.Schema()
+		viewOutputNames = viewLogicalPlan.OutputNames()
+	}
+
 	for i, col := range tbl.Columns {
 		if col.Hidden {
 			continue
 		}
+
+		ft := &col.FieldType
+		if viewSchema != nil {
+			// If this is a view, replace the column with the view column.
+			idx := expression.FindFieldNameIdxByColName(viewOutputNames, col.Name.L)
+			if idx >= 0 {
+				col1 := viewSchema.Columns[idx]
+				ft = col1.GetType()
+			}
+		}
+
 		var charMaxLen, charOctLen, numericPrecision, numericScale, datetimePrecision interface{}
-		colLen, decimal := col.Flen, col.Decimal
-		defaultFlen, defaultDecimal := mysql.GetDefaultFieldLengthAndDecimal(col.Tp)
+		colLen, decimal := ft.Flen, ft.Decimal
+		defaultFlen, defaultDecimal := mysql.GetDefaultFieldLengthAndDecimal(ft.Tp)
 		if decimal == types.UnspecifiedLength {
 			decimal = defaultDecimal
 		}
 		if colLen == types.UnspecifiedLength {
 			colLen = defaultFlen
 		}
-		if col.Tp == mysql.TypeSet {
+		if ft.Tp == mysql.TypeSet {
 			// Example: In MySQL set('a','bc','def','ghij') has length 13, because
 			// len('a')+len('bc')+len('def')+len('ghij')+len(ThreeComma)=13
 			// Reference link: https://bugs.mysql.com/bug.php?id=22613
 			colLen = 0
-			for _, ele := range col.Elems {
+			for _, ele := range ft.Elems {
 				colLen += len(ele)
 			}
-			if len(col.Elems) != 0 {
-				colLen += (len(col.Elems) - 1)
+			if len(ft.Elems) != 0 {
+				colLen += (len(ft.Elems) - 1)
 			}
 			charMaxLen = colLen
-			charOctLen = calcCharOctLength(colLen, col.Charset)
-		} else if col.Tp == mysql.TypeEnum {
+			charOctLen = calcCharOctLength(colLen, ft.Charset)
+		} else if ft.Tp == mysql.TypeEnum {
 			// Example: In MySQL enum('a', 'ab', 'cdef') has length 4, because
 			// the longest string in the enum is 'cdef'
 			// Reference link: https://bugs.mysql.com/bug.php?id=22613
 			colLen = 0
-			for _, ele := range col.Elems {
+			for _, ele := range ft.Elems {
 				if len(ele) > colLen {
 					colLen = len(ele)
 				}
 			}
 			charMaxLen = colLen
-			charOctLen = calcCharOctLength(colLen, col.Charset)
-		} else if types.IsString(col.Tp) {
+			charOctLen = calcCharOctLength(colLen, ft.Charset)
+		} else if types.IsString(ft.Tp) {
 			charMaxLen = colLen
-			charOctLen = calcCharOctLength(colLen, col.Charset)
-		} else if types.IsTypeFractionable(col.Tp) {
+			charOctLen = calcCharOctLength(colLen, ft.Charset)
+		} else if types.IsTypeFractionable(ft.Tp) {
 			datetimePrecision = decimal
-		} else if types.IsTypeNumeric(col.Tp) {
+		} else if types.IsTypeNumeric(ft.Tp) {
 			numericPrecision = colLen
-			if col.Tp != mysql.TypeFloat && col.Tp != mysql.TypeDouble {
+			if ft.Tp != mysql.TypeFloat && ft.Tp != mysql.TypeDouble {
 				numericScale = decimal
 			} else if decimal != -1 {
 				numericScale = decimal
 			}
 		}
-		columnType := col.FieldType.InfoSchemaStr()
+		columnType := ft.InfoSchemaStr()
 		columnDesc := table.NewColDesc(table.ToColumn(col))
 		var columnDefault interface{}
 		if columnDesc.DefaultValue != nil {
 			columnDefault = fmt.Sprintf("%v", columnDesc.DefaultValue)
 		}
 		record := types.MakeDatums(
-			infoschema.CatalogVal,                // TABLE_CATALOG
-			schema.Name.O,                        // TABLE_SCHEMA
-			tbl.Name.O,                           // TABLE_NAME
-			col.Name.O,                           // COLUMN_NAME
-			i+1,                                  // ORIGINAL_POSITION
-			columnDefault,                        // COLUMN_DEFAULT
-			columnDesc.Null,                      // IS_NULLABLE
-			types.TypeToStr(col.Tp, col.Charset), // DATA_TYPE
-			charMaxLen,                           // CHARACTER_MAXIMUM_LENGTH
-			charOctLen,                           // CHARACTER_OCTET_LENGTH
-			numericPrecision,                     // NUMERIC_PRECISION
-			numericScale,                         // NUMERIC_SCALE
-			datetimePrecision,                    // DATETIME_PRECISION
-			columnDesc.Charset,                   // CHARACTER_SET_NAME
-			columnDesc.Collation,                 // COLLATION_NAME
-			columnType,                           // COLUMN_TYPE
-			columnDesc.Key,                       // COLUMN_KEY
-			columnDesc.Extra,                     // EXTRA
-			"select,insert,update,references",    // PRIVILEGES
-			columnDesc.Comment,                   // COLUMN_COMMENT
-			col.GeneratedExprString,              // GENERATION_EXPRESSION
+			infoschema.CatalogVal,              // TABLE_CATALOG
+			schema.Name.O,                      // TABLE_SCHEMA
+			tbl.Name.O,                         // TABLE_NAME
+			col.Name.O,                         // COLUMN_NAME
+			i+1,                                // ORIGINAL_POSITION
+			columnDefault,                      // COLUMN_DEFAULT
+			columnDesc.Null,                    // IS_NULLABLE
+			types.TypeToStr(ft.Tp, ft.Charset), // DATA_TYPE
+			charMaxLen,                         // CHARACTER_MAXIMUM_LENGTH
+			charOctLen,                         // CHARACTER_OCTET_LENGTH
+			numericPrecision,                   // NUMERIC_PRECISION
+			numericScale,                       // NUMERIC_SCALE
+			datetimePrecision,                  // DATETIME_PRECISION
+			columnDesc.Charset,                 // CHARACTER_SET_NAME
+			columnDesc.Collation,               // COLLATION_NAME
+			columnType,                         // COLUMN_TYPE
+			columnDesc.Key,                     // COLUMN_KEY
+			columnDesc.Extra,                   // EXTRA
+			"select,insert,update,references",  // PRIVILEGES
+			columnDesc.Comment,                 // COLUMN_COMMENT
+			col.GeneratedExprString,            // GENERATION_EXPRESSION
 		)
 		e.rows = append(e.rows, record)
 	}

executor/infoschema_reader_test.go

@@ -981,3 +981,59 @@ func (s *testInfoschemaTableSuite) TestTablesPKType(c *C) {
 	tk.MustQuery("SELECT TIDB_PK_TYPE FROM information_schema.tables where table_schema = 'test' and table_name = 't_common'").Check(testkit.Rows("CLUSTERED"))
 	tk.MustQuery("SELECT TIDB_PK_TYPE FROM information_schema.tables where table_schema = 'INFORMATION_SCHEMA' and table_name = 'TABLES'").Check(testkit.Rows("NONCLUSTERED"))
 }
+
+// https://github.com/pingcap/tidb/issues/32459.
+func (s *testInfoschemaTableSuite) TestJoinSystemTableContainsView(c *C) {
+	tk := testkit.NewTestKitWithInit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("create table t (a timestamp, b int);")
+	tk.MustExec("insert into t values (null, 100);")
+	tk.MustExec("create view v as select * from t;")
+	// This is used by grafana when TiDB is specified as the data source.
+	// See https://github.com/grafana/grafana/blob/e86b6662a187c77656f72bef3b0022bf5ced8b98/public/app/plugins/datasource/mysql/meta_query.ts#L31
+	for i := 0; i < 10; i++ {
+		tk.MustQuery(`
+SELECT
+    table_name as table_name,
+    ( SELECT
+        column_name as column_name
+      FROM information_schema.columns c
+      WHERE
+        c.table_schema = t.table_schema AND
+        c.table_name = t.table_name AND
+        c.data_type IN ('timestamp', 'datetime')
+      ORDER BY ordinal_position LIMIT 1
+    ) AS time_column,
+    ( SELECT
+        column_name AS column_name
+      FROM information_schema.columns c
+      WHERE
+        c.table_schema = t.table_schema AND
+        c.table_name = t.table_name AND
+        c.data_type IN('float', 'int', 'bigint')
+      ORDER BY ordinal_position LIMIT 1
+    ) AS value_column
+  FROM information_schema.tables t
+  WHERE
+    t.table_schema = database() AND
+    EXISTS
+    ( SELECT 1
+      FROM information_schema.columns c
+      WHERE
+        c.table_schema = t.table_schema AND
+        c.table_name = t.table_name AND
+        c.data_type IN ('timestamp', 'datetime')
+    ) AND
+    EXISTS
+    ( SELECT 1
+      FROM information_schema.columns c
+      WHERE
+        c.table_schema = t.table_schema AND
+        c.table_name = t.table_name AND
+        c.data_type IN('float', 'int', 'bigint')
+    )
+  LIMIT 1
+;
+`).Check(testkit.Rows("t a b"))
+	}
+}

executor/show.go

@@ -1761,9 +1761,15 @@ func (e *ShowExec) fetchShowBuiltins() error {
 // Because view's underlying table's column could change or recreate, so view's column type may change over time.
 // To avoid this situation we need to generate a logical plan and extract current column types from Schema.
 func tryFillViewColumnType(ctx context.Context, sctx sessionctx.Context, is infoschema.InfoSchema, dbName model.CIStr, tbl *model.TableInfo) error {
-	if tbl.IsView() {
+	if !tbl.IsView() {
+		return nil
+	}
+	// We need to run the build plan process in another session because there may be
+	// multiple goroutines running at the same time while session is not goroutine-safe.
+	// Take joining system table as an example, `fetchBuildSideRows` and `fetchProbeSideChunks` can be run concurrently.
+	return runWithSystemSession(sctx, func(s sessionctx.Context) error {
 		// Retrieve view columns info.
-		planBuilder, _ := plannercore.NewPlanBuilder().Init(sctx, is, &hint.BlockHintProcessor{})
+		planBuilder, _ := plannercore.NewPlanBuilder().Init(s, is, &hint.BlockHintProcessor{})
 		if viewLogicalPlan, err := planBuilder.BuildDataSourceFromView(ctx, dbName, tbl); err == nil {
 			viewSchema := viewLogicalPlan.Schema()
 			viewOutputNames := viewLogicalPlan.OutputNames()
@@ -1779,6 +1785,23 @@ func tryFillViewColumnType(ctx context.Context, sctx sessionctx.Context, is info
 		} else {
 			return err
 		}
+		return nil
+	})
+}
+
+func runWithSystemSession(sctx sessionctx.Context, fn func(sessionctx.Context) error) error {
+	b := &baseExecutor{ctx: sctx}
+	sysCtx, err := b.getSysSession()
+	if err != nil {
+		return err
 	}
-	return nil
+	// TODO(tangenta): remove the CurrentDB assignment after
+	// https://github.com/pingcap/tidb/issues/34090 is fixed.
+	originDB := sysCtx.GetSessionVars().CurrentDB
+	sysCtx.GetSessionVars().CurrentDB = sctx.GetSessionVars().CurrentDB
+	defer func() {
+		sysCtx.GetSessionVars().CurrentDB = originDB
+	}()
+	defer b.releaseSysSession(sysCtx)
+	return fn(sysCtx)
 }

infoschema/cluster_tables_test.go

@@ -0,0 +1,79 @@
+// Copyright 2021 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,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package infoschema_test
+
+import (
+	"fmt"
+	"net/http/httptest"
+	"strconv"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/pingcap/parser/auth"
+	"github.com/pingcap/tidb/domain"
+	"github.com/pingcap/tidb/kv"
+	"github.com/pingcap/tidb/testkit"
+	"github.com/stretchr/testify/require"
+	"google.golang.org/grpc"
+)
+
+type clusterTablesSuite struct {
+	store      kv.Storage
+	dom        *domain.Domain
+	rpcserver  *grpc.Server
+	httpServer *httptest.Server
+	mockAddr   string
+	listenAddr string
+	startTime  time.Time
+}
+
+func TestStmtSummaryIssue35340(t *testing.T) {
+	s := new(clusterTablesSuite)
+	s.store, s.dom = testkit.CreateMockStoreAndDomain(t)
+
+	tk := s.newTestKitWithRoot(t)
+	tk.MustExec("set global tidb_stmt_summary_refresh_interval=1800")
+	tk.MustExec("set global tidb_stmt_summary_max_stmt_count = 3000")
+	for i := 0; i < 100; i++ {
+		user := "user" + strconv.Itoa(i)
+		tk.MustExec(fmt.Sprintf("create user '%v'@'localhost'", user))
+	}
+	tk.MustExec("flush privileges")
+	var wg sync.WaitGroup
+	for i := 0; i < 10; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			tk := s.newTestKitWithRoot(t)
+			for j := 0; j < 100; j++ {
+				user := "user" + strconv.Itoa(j)
+				require.True(t, tk.Session().Auth(&auth.UserIdentity{
+					Username: user,
+					Hostname: "localhost",
+				}, nil, nil))
+				tk.MustQuery("select count(*) from information_schema.statements_summary;")
+			}
+		}()
+	}
+	wg.Wait()
+}
+
+func (s *clusterTablesSuite) newTestKitWithRoot(t *testing.T) *testkit.TestKit {
+	tk := testkit.NewTestKit(t, s.store)
+	tk.MustExec("use test")
+	require.True(t, tk.Session().Auth(&auth.UserIdentity{Username: "root", Hostname: "%"}, nil, nil))
+	return tk
+}

testkit/mockstore.go

@@ -11,13 +11,16 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build !codes
 // +build !codes
 
 package testkit
 
 import (
 	"testing"
+	"time"
 
+	"github.com/pingcap/tidb/domain"
 	"github.com/pingcap/tidb/kv"
 	"github.com/pingcap/tidb/session"
 	"github.com/pingcap/tidb/store/mockstore"
@@ -44,3 +47,26 @@ func CreateMockStore(t *testing.T) (store kv.Storage, clean func()) {
 
 	return
 }
+
+// CreateMockStoreAndDomain return a new mock kv.Storage and *domain.Domain.
+func CreateMockStoreAndDomain(t testing.TB, opts ...mockstore.MockTiKVStoreOption) (kv.Storage, *domain.Domain) {
+	store, err := mockstore.NewMockStore(opts...)
+	require.NoError(t, err)
+	return store, bootstrap(t, store, 0)
+}
+
+func bootstrap(t testing.TB, store kv.Storage, lease time.Duration) *domain.Domain {
+	session.SetSchemaLease(lease)
+	session.DisableStats4Test()
+	dom, err := session.BootstrapSession(store)
+	require.NoError(t, err)
+
+	dom.SetStatsUpdating(true)
+
+	t.Cleanup(func() {
+		dom.Close()
+		err := store.Close()
+		require.NoError(t, err)
+	})
+	return dom
+}