session: cleanup some duplicated code (pingcap#19980)

session/session.go

@@ -1077,32 +1077,18 @@ func (s *session) Execute(ctx context.Context, sql string) (recordSets []sqlexec
 		logutil.Eventf(ctx, "execute: %s", sql)
 	}
 
-	charsetInfo, collation := s.sessionVars.GetCharsetInfo()
-	parseStartTime := time.Now()
-	stmtNodes, warns, err := s.ParseSQL(ctx, sql, charsetInfo, collation)
+	stmtNodes, err := s.Parse(ctx, sql)
 	if err != nil {
-		s.rollbackOnError(ctx)
-
-		// Only print log message when this SQL is from the user.
-		// Mute the warning for internal SQLs.
-		if !s.sessionVars.InRestrictedSQL {
-			logutil.Logger(ctx).Warn("parse SQL failed", zap.Error(err), zap.String("SQL", sql))
-		}
-		return nil, util.SyntaxError(err)
+		return nil, err
 	}
 	if len(stmtNodes) != 1 {
 		return nil, errors.New("Execute() API doesn't support multiple statements any more")
 	}
-	durParse := time.Since(parseStartTime)
-	s.GetSessionVars().DurationParse = durParse
 
 	rs, err := s.ExecuteStmt(ctx, stmtNodes[0])
 	if err != nil {
 		s.sessionVars.StmtCtx.AppendError(err)
 	}
-	for _, warn := range warns {
-		s.sessionVars.StmtCtx.AppendWarning(util.SyntaxWarn(warn))
-	}
 	if rs == nil {
 		return nil, err
 	}