*: record previous statement when commit is slow

executor/adapter.go

@@ -177,6 +177,7 @@ func (a *recordSet) NewChunk() *chunk.Chunk {
 func (a *recordSet) Close() error {
 	err := a.executor.Close()
 	a.stmt.LogSlowQuery(a.txnStartTS, a.lastErr == nil)
+	a.stmt.Ctx.GetSessionVars().PrevStmt = a.stmt.OriginText()
 	a.stmt.logAudit()
 	return err
 }
@@ -682,6 +683,16 @@ func (a *ExecStmt) logAudit() {
 	}
 }
 
+// FormatSQL is used to format the original SQL, e.g. truncating long SQL, appending prepared arguments.
+func FormatSQL(sql string, sessVars *variable.SessionVars) string {
+	cfg := config.GetGlobalConfig()
+	length := len(sql)
+	if maxQueryLen := atomic.LoadUint64(&cfg.Log.QueryLogMaxLen); uint64(length) > maxQueryLen {
+		sql = fmt.Sprintf("%.*q(len:%d)", maxQueryLen, sql, length)
+	}
+	return QueryReplacer.Replace(sql) + sessVars.GetExecuteArgumentsInfo()
+}
+
 // LogSlowQuery is used to print the slow query in the log files.
 func (a *ExecStmt) LogSlowQuery(txnTS uint64, succ bool) {
 	sessVars := a.Ctx.GetSessionVars()
@@ -695,11 +706,7 @@ func (a *ExecStmt) LogSlowQuery(txnTS uint64, succ bool) {
 	if costTime < threshold && level > zapcore.DebugLevel {
 		return
 	}
-	sql := a.Text
-	if maxQueryLen := atomic.LoadUint64(&cfg.Log.QueryLogMaxLen); uint64(len(sql)) > maxQueryLen {
-		sql = fmt.Sprintf("%.*q(len:%d)", maxQueryLen, sql, len(a.Text))
-	}
-	sql = QueryReplacer.Replace(sql) + sessVars.GetExecuteArgumentsInfo()
+	sql := FormatSQL(a.Text, sessVars)
 
 	var tableIDs, indexNames string
 	if len(sessVars.StmtCtx.TableIDs) > 0 {
@@ -712,38 +719,28 @@ func (a *ExecStmt) LogSlowQuery(txnTS uint64, succ bool) {
 	copTaskInfo := sessVars.StmtCtx.CopTasksDetails()
 	statsInfos := plannercore.GetStatsInfo(a.Plan)
 	memMax := sessVars.StmtCtx.MemTracker.MaxConsumed()
+	_, digest := sessVars.StmtCtx.SQLDigest()
+	slowItems := &variable.SlowQueryLogItems{
+		TxnTS:       txnTS,
+		SQL:         sql,
+		Digest:      digest,
+		TimeTotal:   costTime,
+		TimeParse:   a.Ctx.GetSessionVars().DurationParse,
+		TimeCompile: a.Ctx.GetSessionVars().DurationCompile,
+		IndexNames:  indexNames,
+		StatsInfos:  statsInfos,
+		CopTasks:    copTaskInfo,
+		ExecDetail:  execDetail,
+		MemMax:      memMax,
+		Succ:        succ,
+	}
+	if _, ok := a.StmtNode.(*ast.CommitStmt); ok {
+		slowItems.PrevStmt = FormatSQL(sessVars.PrevStmt, sessVars)
+	}
 	if costTime < threshold {
-		_, digest := sessVars.StmtCtx.SQLDigest()
-		logutil.SlowQueryLogger.Debug(sessVars.SlowLogFormat(&variable.SlowQueryLogItems{
-			TxnTS:       txnTS,
-			SQL:         sql,
-			Digest:      digest,
-			TimeTotal:   costTime,
-			TimeParse:   a.Ctx.GetSessionVars().DurationParse,
-			TimeCompile: a.Ctx.GetSessionVars().DurationCompile,
-			IndexNames:  indexNames,
-			StatsInfos:  statsInfos,
-			CopTasks:    copTaskInfo,
-			ExecDetail:  execDetail,
-			MemMax:      memMax,
-			Succ:        succ,
-		}))
+		logutil.SlowQueryLogger.Debug(sessVars.SlowLogFormat(slowItems))
 	} else {
-		_, digest := sessVars.StmtCtx.SQLDigest()
-		logutil.SlowQueryLogger.Warn(sessVars.SlowLogFormat(&variable.SlowQueryLogItems{
-			TxnTS:       txnTS,
-			SQL:         sql,
-			Digest:      digest,
-			TimeTotal:   costTime,
-			TimeParse:   a.Ctx.GetSessionVars().DurationParse,
-			TimeCompile: a.Ctx.GetSessionVars().DurationCompile,
-			IndexNames:  indexNames,
-			StatsInfos:  statsInfos,
-			CopTasks:    copTaskInfo,
-			ExecDetail:  execDetail,
-			MemMax:      memMax,
-			Succ:        succ,
-		}))
+		logutil.SlowQueryLogger.Warn(sessVars.SlowLogFormat(slowItems))
 		metrics.TotalQueryProcHistogram.Observe(costTime.Seconds())
 		metrics.TotalCopProcHistogram.Observe(execDetail.ProcessTime.Seconds())
 		metrics.TotalCopWaitHistogram.Observe(execDetail.WaitTime.Seconds())

infoschema/slow_log.go

@@ -60,6 +60,7 @@ var slowQueryCols = []columnInfo{
 	{variable.SlowLogCopWaitAddr, mysql.TypeVarchar, 64, 0, nil, nil},
 	{variable.SlowLogMemMax, mysql.TypeLonglong, 20, 0, nil, nil},
 	{variable.SlowLogSucc, mysql.TypeTiny, 1, 0, nil, nil},
+	{variable.SlowLogPrevStmt, mysql.TypeLongBlob, types.UnspecifiedLength, 0, nil, nil},
 	{variable.SlowLogQuerySQLStr, mysql.TypeLongBlob, types.UnspecifiedLength, 0, nil, nil},
 }
 
@@ -112,15 +113,19 @@ func ParseSlowLog(tz *time.Location, reader *bufio.Reader) ([][]types.Datum, err
 			// Parse slow log field.
 			if strings.HasPrefix(line, variable.SlowLogRowPrefixStr) {
 				line = line[len(variable.SlowLogRowPrefixStr):]
-				fieldValues := strings.Split(line, " ")
-				for i := 0; i < len(fieldValues)-1; i += 2 {
-					field := fieldValues[i]
-					if strings.HasSuffix(field, ":") {
-						field = field[:len(field)-1]
-					}
-					err = st.setFieldValue(tz, field, fieldValues[i+1])
-					if err != nil {
-						return rows, err
+				if strings.HasPrefix(line, variable.SlowLogPrevStmtPrefix) {
+					st.prevStmt = line[len(variable.SlowLogPrevStmtPrefix):]
+				} else {
+					fieldValues := strings.Split(line, " ")
+					for i := 0; i < len(fieldValues)-1; i += 2 {
+						field := fieldValues[i]
+						if strings.HasSuffix(field, ":") {
+							field = field[:len(field)-1]
+						}
+						err = st.setFieldValue(tz, field, fieldValues[i+1])
+						if err != nil {
+							return rows, err
+						}
 					}
 				}
 			} else if strings.HasSuffix(line, variable.SlowLogSQLSuffixStr) {
@@ -195,6 +200,7 @@ type slowQueryTuple struct {
 	maxWaitTime       float64
 	maxWaitAddress    string
 	memMax            int64
+	prevStmt          string
 	sql               string
 	isInternal        bool
 	succ              bool
@@ -313,6 +319,7 @@ func (st *slowQueryTuple) convertToDatumRow() []types.Datum {
 	} else {
 		record = append(record, types.NewIntDatum(0))
 	}
+	record = append(record, types.NewStringDatum(st.prevStmt))
 	record = append(record, types.NewStringDatum(st.sql))
 	return record
 }

infoschema/slow_log_test.go

@@ -38,6 +38,7 @@ func (s *testSuite) TestParseSlowLogFile(c *C) {
 # Cop_wait_avg: 0.05 Cop_wait_p90: 0.6 Cop_wait_max: 0.8 Cop_wait_addr: 0.0.0.0:20160
 # Mem_max: 70724
 # Succ: false
+# Prev_stmt: update t set i = 1;
 select * from t;`)
 	reader := bufio.NewReader(slowLog)
 	loc, err := time.LoadLocation("Asia/Shanghai")
@@ -54,7 +55,7 @@ select * from t;`)
 		}
 		recordString += str
 	}
-	expectRecordString := "2019-04-28 15:24:04.309074,405888132465033227,,,0,0.216905,0.021,0,0,1,637,0,,,1,42a1c8aae6f133e934d4bf0147491709a8812ea05ff8819ec522780fe657b772,t1:1,t2:2,0.1,0.2,0.03,127.0.0.1:20160,0.05,0.6,0.8,0.0.0.0:20160,70724,0,select * from t;"
+	expectRecordString := "2019-04-28 15:24:04.309074,405888132465033227,,,0,0.216905,0.021,0,0,1,637,0,,,1,42a1c8aae6f133e934d4bf0147491709a8812ea05ff8819ec522780fe657b772,t1:1,t2:2,0.1,0.2,0.03,127.0.0.1:20160,0.05,0.6,0.8,0.0.0.0:20160,70724,0,update t set i = 1;,select * from t;"
 	c.Assert(expectRecordString, Equals, recordString)
 
 	// fix sql contain '# ' bug

infoschema/tables_test.go

@@ -466,6 +466,7 @@ func (s *testTableSuite) TestSlowQuery(c *C) {
 # Cop_wait_avg: 0.05 Cop_wait_p90: 0.6 Cop_wait_max: 0.8 Cop_wait_addr: 0.0.0.0:20160
 # Mem_max: 70724
 # Succ: true
+# Prev_stmt: update t set i = 2;
 select * from t_slim;`))
 	c.Assert(f.Sync(), IsNil)
 	c.Assert(err, IsNil)
@@ -474,10 +475,10 @@ select * from t_slim;`))
 	tk.MustExec("set time_zone = '+08:00';")
 	re := tk.MustQuery("select * from information_schema.slow_query")
 	re.Check(testutil.RowsWithSep("|",
-		"2019-02-12 19:33:56.571953|406315658548871171|root|127.0.0.1|6|4.895492|0.161|0.101|0.092|1|100001|100000|test||0|42a1c8aae6f133e934d4bf0147491709a8812ea05ff8819ec522780fe657b772|t1:1,t2:2|0.1|0.2|0.03|127.0.0.1:20160|0.05|0.6|0.8|0.0.0.0:20160|70724|1|select * from t_slim;"))
+		"2019-02-12 19:33:56.571953|406315658548871171|root|127.0.0.1|6|4.895492|0.161|0.101|0.092|1|100001|100000|test||0|42a1c8aae6f133e934d4bf0147491709a8812ea05ff8819ec522780fe657b772|t1:1,t2:2|0.1|0.2|0.03|127.0.0.1:20160|0.05|0.6|0.8|0.0.0.0:20160|70724|1|update t set i = 2;|select * from t_slim;"))
 	tk.MustExec("set time_zone = '+00:00';")
 	re = tk.MustQuery("select * from information_schema.slow_query")
-	re.Check(testutil.RowsWithSep("|", "2019-02-12 11:33:56.571953|406315658548871171|root|127.0.0.1|6|4.895492|0.161|0.101|0.092|1|100001|100000|test||0|42a1c8aae6f133e934d4bf0147491709a8812ea05ff8819ec522780fe657b772|t1:1,t2:2|0.1|0.2|0.03|127.0.0.1:20160|0.05|0.6|0.8|0.0.0.0:20160|70724|1|select * from t_slim;"))
+	re.Check(testutil.RowsWithSep("|", "2019-02-12 11:33:56.571953|406315658548871171|root|127.0.0.1|6|4.895492|0.161|0.101|0.092|1|100001|100000|test||0|42a1c8aae6f133e934d4bf0147491709a8812ea05ff8819ec522780fe657b772|t1:1,t2:2|0.1|0.2|0.03|127.0.0.1:20160|0.05|0.6|0.8|0.0.0.0:20160|70724|1|update t set i = 2;|select * from t_slim;"))
 
 	// Test for long query.
 	_, err = f.Write([]byte(`

session/tidb.go

@@ -218,6 +218,7 @@ func runStmt(ctx context.Context, sctx sessionctx.Context, s sqlexec.Statement)
 		// then it could include the transaction commit time.
 		if rs == nil {
 			s.(*executor.ExecStmt).LogSlowQuery(origTxnCtx.StartTS, err == nil)
+			sessVars.PrevStmt = s.OriginText()
 		}
 	}()
 

sessionctx/variable/session.go

@@ -409,11 +409,14 @@ type SessionVars struct {
 	// StartTime is the start time of the last query.
 	StartTime time.Time
 
-	// DurationParse is the duration of pasing SQL string to AST of the last query.
+	// DurationParse is the duration of parsing SQL string to AST of the last query.
 	DurationParse time.Duration
 
 	// DurationCompile is the duration of compiling AST to execution plan of the last query.
 	DurationCompile time.Duration
+
+	// PrevStmt is used to store the previous executed statement in the current session.
+	PrevStmt string
 }
 
 // ConnectionInfo present connection used by audit.
@@ -1046,6 +1049,10 @@ const (
 	SlowLogMemMax = "Mem_max"
 	// SlowLogSucc is used to indicate whether this sql execute successfully.
 	SlowLogSucc = "Succ"
+	// SlowLogPrevStmt is used to show the previous executed statement.
+	SlowLogPrevStmt = "Prev_stmt"
+	// SlowLogPrevStmtPrefix is the prefix of Prev_stmt in slow log file.
+	SlowLogPrevStmtPrefix = SlowLogPrevStmt + SlowLogSpaceMarkStr
 )
 
 // SlowQueryLogItems is a collection of items that should be included in the
@@ -1063,6 +1070,7 @@ type SlowQueryLogItems struct {
 	ExecDetail  execdetails.ExecDetails
 	MemMax      int64
 	Succ        bool
+	PrevStmt    string
 }
 
 // SlowLogFormat uses for formatting slow log.
@@ -1083,6 +1091,7 @@ type SlowQueryLogItems struct {
 // # Cop_wait: Avg_time: 10ms P90_time: 20ms Max_time: 30ms Max_Addr: 10.6.131.79
 // # Memory_max: 4096
 // # Succ: true
+// # Prev_stmt: begin;
 // select * from t_slim;
 func (s *SessionVars) SlowLogFormat(logItems *SlowQueryLogItems) string {
 	var buf bytes.Buffer
@@ -1150,6 +1159,10 @@ func (s *SessionVars) SlowLogFormat(logItems *SlowQueryLogItems) string {
 
 	writeSlowLogItem(&buf, SlowLogSucc, strconv.FormatBool(logItems.Succ))
 
+	if logItems.PrevStmt != "" {
+		writeSlowLogItem(&buf, SlowLogPrevStmt, logItems.PrevStmt)
+	}
+
 	buf.WriteString(logItems.SQL)
 	if len(logItems.SQL) == 0 || logItems.SQL[len(logItems.SQL)-1] != ';' {
 		buf.WriteString(";")