*: refine mysql.tidb_mdl_view

pkg/infoschema/test/clustertablestest/cluster_tables_test.go

@@ -41,6 +41,7 @@ import (
 	"github.com/pingcap/tidb/pkg/parser"
 	"github.com/pingcap/tidb/pkg/parser/auth"
 	"github.com/pingcap/tidb/pkg/parser/mysql"
+	"github.com/pingcap/tidb/pkg/privilege/privileges"
 	"github.com/pingcap/tidb/pkg/server"
 	"github.com/pingcap/tidb/pkg/store/helper"
 	"github.com/pingcap/tidb/pkg/store/mockstore"
@@ -842,6 +843,11 @@ func TestMDLView(t *testing.T) {
 		{"add column", "create table t(a int)", "alter table test.t add column b int", []string{"select 1", "select * from t"}, "[\"begin\",\"select ?\",\"select * from `t`\"]"},
 		{"change column in 1 step", "create table t(a int)", "alter table test.t change column a b int", []string{"select 1", "select * from t"}, "[\"begin\",\"select ?\",\"select * from `t`\"]"},
 	}
+	save := privileges.SkipWithGrant
+	privileges.SkipWithGrant = true
+	defer func() {
+		privileges.SkipWithGrant = save
+	}()
 	for _, c := range testCases {
 		t.Run(c.name, func(t *testing.T) {
 			// setup suite

pkg/session/bootstrap.go

@@ -459,19 +459,18 @@ const (
 	);`
 	// CreateMDLView is a view about metadata locks.
 	CreateMDLView = `CREATE OR REPLACE VIEW mysql.tidb_mdl_view as (
-		SELECT job_id,
+		SELECT ddl_jobs.job_id,
 			db_name,
 			table_name,
 			query,
 			session_id,
-			txnstart,
+			cluster_tidb_trx.start_time,
 			tidb_decode_sql_digests(all_sql_digests, 4096) AS SQL_DIGESTS
 		FROM information_schema.ddl_jobs,
-			information_schema.cluster_tidb_trx,
-			information_schema.cluster_processlist
-		WHERE (ddl_jobs.state != 'synced' and ddl_jobs.state != 'cancelled')
-			AND Find_in_set(ddl_jobs.table_id, cluster_tidb_trx.related_table_ids)
-			AND cluster_tidb_trx.session_id = cluster_processlist.id
+			mysql.tidb_mdl_info,
+			information_schema.cluster_tidb_trx
+		WHERE ddl_jobs.job_id = tidb_mdl_info.job_id
+			AND CONCAT(',', tidb_mdl_info.table_ids, ',') REGEXP CONCAT(',', REPLACE(cluster_tidb_trx.related_table_ids, ',', '|'), ',') != 0
 	);`
 
 	// CreatePlanReplayerStatusTable is a table about plan replayer status
@@ -1022,14 +1021,18 @@ const (
 	//   write mDDLTableVersion into `mysql.tidb` table
 	version178 = 178
 
-	// vresion 179
+	// version 179
 	//   enlarge `VARIABLE_VALUE` of `mysql.global_variables` from `varchar(1024)` to `varchar(16383)`.
 	version179 = 179
+
+	// version 180
+	//   replace `mysql.tidb_mdl_view` table
+	version180 = 180
 )
 
 // currentBootstrapVersion is defined as a variable, so we can modify its value for testing.
 // please make sure this is the largest version
-var currentBootstrapVersion int64 = version179
+var currentBootstrapVersion int64 = version180
 
 // DDL owner key's expired time is ManagerSessionTTL seconds, we should wait the time and give more time to have a chance to finish it.
 var internalSQLTimeout = owner.ManagerSessionTTL + 15
@@ -1184,6 +1187,7 @@ var (
 		upgradeToVer177,
 		upgradeToVer178,
 		upgradeToVer179,
+		upgradeToVer180,
 	}
 )
 
@@ -2892,6 +2896,13 @@ func upgradeToVer179(s Session, ver int64) {
 	doReentrantDDL(s, "ALTER TABLE mysql.global_variables MODIFY COLUMN `VARIABLE_VALUE` varchar(16383)")
 }
 
+func upgradeToVer180(s Session, ver int64) {
+	if ver >= version180 {
+		return
+	}
+	doReentrantDDL(s, CreateMDLView)
+}
+
 func writeOOMAction(s Session) {
 	comment := "oom-action is `log` by default in v3.0.x, `cancel` by default in v4.0.11+"
 	mustExecute(s, `INSERT HIGH_PRIORITY INTO %n.%n VALUES (%?, %?, %?) ON DUPLICATE KEY UPDATE VARIABLE_VALUE= %?`,

pkg/sessionctx/variable/session.go

@@ -2084,6 +2084,7 @@ func NewSessionVars(hctx HookContext) *SessionVars {
 	if EnableRowLevelChecksum.Load() {
 		vars.EnableRowLevelChecksum = true
 	}
+	vars.systems[MaxAllowedPacket] = strconv.Itoa(int(DefMaxAllowedPacket))
 	vars.systems[CharacterSetConnection], vars.systems[CollationConnection] = charset.GetDefaultCharsetAndCollate()
 	return vars
 }