metric: replace QueryDurationHistogram's "general" type to more detai…

…l stmt type (pingcap#8819)

executor/adapter.go

@@ -43,6 +43,7 @@ import (
 	log "github.com/sirupsen/logrus"
 )
 
+// processinfoSetter is the interface use to set current running process info.
 type processinfoSetter interface {
 	SetProcessInfo(string, time.Time, byte)
 }
@@ -235,6 +236,7 @@ func (a *ExecStmt) Exec(ctx context.Context) (sqlexec.RecordSet, error) {
 		}
 		// Update processinfo, ShowProcess() will use it.
 		pi.SetProcessInfo(sql, time.Now(), cmd)
+		a.Ctx.GetSessionVars().StmtCtx.StmtType = GetStmtLabel(a.StmtNode)
 	}
 
 	// If the executor doesn't return any result to the client, we execute it without delay.

server/conn.go

@@ -686,7 +686,12 @@ func (cc *clientConn) addMetrics(cmd byte, startTime time.Time, err error) {
 	} else {
 		metrics.QueryTotalCounter.WithLabelValues(label, "OK").Inc()
 	}
-	metrics.QueryDurationHistogram.WithLabelValues(metrics.LblGeneral).Observe(time.Since(startTime).Seconds())
+	stmtType := cc.ctx.GetSessionVars().StmtCtx.StmtType
+	sqlType := metrics.LblGeneral
+	if stmtType != "" {
+		sqlType = stmtType
+	}
+	metrics.QueryDurationHistogram.WithLabelValues(sqlType).Observe(time.Since(startTime).Seconds())
 }
 
 // dispatch handles client request based on command which is the first byte of the data.

sessionctx/stmtctx/stmtctx.go

@@ -111,6 +111,7 @@ type StatementContext struct {
 	IndexIDs         []int64
 	NowTs            time.Time
 	SysTs            time.Time
+	StmtType         string
 }
 
 // AddAffectedRows adds affected rows.