*: add wait lock time in tidb_trx (pingcap#43105)

close pingcap#43104

infoschema/tables.go

@@ -1493,6 +1493,7 @@ var tableTiDBTrxCols = []columnInfo{
 	{name: txninfo.DBStr, tp: mysql.TypeVarchar, size: 64, comment: "The schema this transaction works on"},
 	{name: txninfo.AllSQLDigestsStr, tp: mysql.TypeBlob, size: types.UnspecifiedLength, comment: "A list of the digests of SQL statements that the transaction has executed"},
 	{name: txninfo.RelatedTableIDsStr, tp: mysql.TypeBlob, size: types.UnspecifiedLength, comment: "A list of the table IDs that the transaction has accessed"},
+	{name: txninfo.WaitingTimeStr, tp: mysql.TypeDouble, size: 22, comment: "Current lock waiting time"},
 }
 
 var tableDeadlocksCols = []columnInfo{

infoschema/test/clustertablestest/tables_test.go

@@ -1522,10 +1522,26 @@ func TestTiDBTrx(t *testing.T) {
 	sm.TxnInfo[1].BlockStartTime.Time = blockTime2
 	tk.Session().SetSessionManager(sm)
 
-	tk.MustQuery("select * from information_schema.TIDB_TRX;").Check(testkit.Rows(
+	tk.MustQuery(`select ID,
+	START_TIME,
+	CURRENT_SQL_DIGEST,
+	CURRENT_SQL_DIGEST_TEXT,
+	STATE,
+	WAITING_START_TIME,
+	MEM_BUFFER_KEYS,
+	MEM_BUFFER_BYTES,
+	SESSION_ID,
+	USER,
+	DB,
+	ALL_SQL_DIGESTS,
+	RELATED_TABLE_IDS
+	from information_schema.TIDB_TRX`).Check(testkit.Rows(
 		"424768545227014155 2021-05-07 12:56:48.001000 "+digest.String()+" update `test_tidb_trx` set `i` = `i` + ? Idle <nil> 1 19 2 root test [] ",
 		"425070846483628033 2021-05-20 21:16:35.778000 <nil> <nil> LockWaiting 2021-05-20 13:18:30.123456 0 19 10 user1 db1 [\"sql1\",\"sql2\",\""+digest.String()+"\"] "))
 
+	rows := tk.MustQuery(`select WAITING_TIME from information_schema.TIDB_TRX where WAITING_TIME is not null`)
+	require.Len(t, rows.Rows(), 1)
+
 	// Test the all_sql_digests column can be directly passed to the tidb_decode_sql_digests function.
 	require.NoError(t, failpoint.Enable("github.com/pingcap/tidb/expression/sqlDigestRetrieverSkipRetrieveGlobal", "return"))
 	defer func() {

session/txninfo/txn_info.go

@@ -138,6 +138,8 @@ const (
 	AllSQLDigestsStr = "ALL_SQL_DIGESTS"
 	// RelatedTableIDsStr is the table id of the TIDB_TRX table's RelatedTableIDs column.
 	RelatedTableIDsStr = "RELATED_TABLE_IDS"
+	// WaitingTimeStr is the column name of the TIDB_TRX table's WaitingTime column.
+	WaitingTimeStr = "WAITING_TIME"
 )
 
 // TxnRunningStateStrs is the names of the TxnRunningStates
@@ -252,6 +254,12 @@ var columnValueGetterMap = map[string]func(*TxnInfo) types.Datum{
 		}
 		return types.NewDatum(str.String())
 	},
+	WaitingTimeStr: func(info *TxnInfo) types.Datum {
+		if !info.BlockStartTime.Valid {
+			return types.NewDatum(nil)
+		}
+		return types.NewFloat64Datum(time.Since(info.BlockStartTime.Time).Seconds())
+	},
 }
 
 // ToDatum Converts the `TxnInfo`'s specified column to `Datum` to show in the `TIDB_TRX` table.