diff --git a/executor/set.go b/executor/set.go
index e4372cc2dd2d1..c17cb5c085fa8 100644
--- a/executor/set.go
+++ b/executor/set.go
@@ -189,7 +189,13 @@ func (e *SetExecutor) setSysVariable(name string, v *expression.VarAssignment) e
 			valStr, err = value.ToString()
 			terror.Log(errors.Trace(err))
 		}
-		logutil.Logger(context.Background()).Info("set session var", zap.Uint64("conn", sessionVars.ConnectionID), zap.String("name", name), zap.String("val", valStr))
+		if name != variable.AutocommitVar {
+			logutil.Logger(context.Background()).Info("set session var", zap.Uint64("conn", sessionVars.ConnectionID), zap.String("name", name), zap.String("val", valStr))
+		} else {
+			// Some applications will set `autocommit` variable before query.
+			// This will print too many unnecessary log info.
+			logutil.Logger(context.Background()).Debug("set session var", zap.Uint64("conn", sessionVars.ConnectionID), zap.String("name", name), zap.String("val", valStr))
+		}
 	}
 
 	return nil
diff --git a/server/conn.go b/server/conn.go
index 2a8e5e6459e84..e04f4d3861346 100644
--- a/server/conn.go
+++ b/server/conn.go
@@ -111,7 +111,7 @@ type clientConn struct {
 
 func (cc *clientConn) String() string {
 	collationStr := mysql.Collations[cc.collation]
-	return fmt.Sprintf("id:%d, addr:%s status:%d, collation:%s, user:%s",
+	return fmt.Sprintf("id:%d, addr:%s status:%b, collation:%s, user:%s",
 		cc.connectionID, cc.bufReadConn.RemoteAddr(), cc.ctx.Status(), collationStr, cc.user,
 	)
 }
@@ -394,6 +394,20 @@ func (cc *clientConn) readOptionalSSLRequestAndHandshakeResponse(ctx context.Con
 	return errors.Trace(err)
 }
 
+func (cc *clientConn) SessionStatusToString() string {
+	status := cc.ctx.Status()
+	inTxn, autoCommit := 0, 0
+	if status&mysql.ServerStatusInTrans > 0 {
+		inTxn = 1
+	}
+	if status&mysql.ServerStatusAutocommit > 0 {
+		autoCommit = 1
+	}
+	return fmt.Sprintf("inTxn:%d, autocommit:%d",
+		inTxn, autoCommit,
+	)
+}
+
 func (cc *clientConn) openSessionAndDoAuth(authData []byte) error {
 	var tlsStatePtr *tls.ConnectionState
 	if cc.tlsConn != nil {
@@ -520,6 +534,8 @@ func (cc *clientConn) Run(ctx context.Context) {
 			}
 			logutil.Logger(ctx).Warn("dispatch error",
 				zap.String("connInfo", cc.String()),
+				zap.String("command", mysql.Command2Str[data[0]]),
+				zap.String("status", cc.SessionStatusToString()),
 				zap.String("sql", queryStrForLog(string(data[1:]))),
 				zap.String("err", errStrForLog(err)),
 			)