Fix bug on migration 147 (#12565)

models/migrations/v147.go

@@ -82,14 +82,15 @@ func createReviewsForCodeComments(x *xorm.Engine) error {
 	if err := x.Sync2(new(Review), new(Comment)); err != nil {
 		return err
 	}
+
+	var updateComment = func(comments []*Comment) error {
 		sess := x.NewSession()
 		defer sess.Close()
 		if err := sess.Begin(); err != nil {
 			return err
 		}
-	if err := sess.Where("review_id = 0 and type = 21").Iterate(new(Comment), func(idx int, bean interface{}) error {
-		comment := bean.(*Comment)
 
+		for _, comment := range comments {
 			review := &Review{
 				Type:             ReviewTypeComment,
 				ReviewerID:       comment.PosterID,
@@ -122,11 +123,32 @@ func createReviewsForCodeComments(x *xorm.Engine) error {
 			}
 
 			comment.ReviewID = review.ID
-		_, err := sess.ID(comment.ID).Cols("review_id").NoAutoTime().Update(comment)
-		return err
-	}); err != nil {
+			if _, err := sess.ID(comment.ID).Cols("review_id").NoAutoTime().Update(comment); err != nil {
 				return err
 			}
+		}
 
 		return sess.Commit()
+	}
+
+	var start = 0
+	var batchSize = 100
+	for {
+		var comments = make([]*Comment, 0, batchSize)
+		if err := x.Where("review_id = 0 and type = 21").Limit(batchSize, start).Find(&comments); err != nil {
+			return err
+		}
+
+		if err := updateComment(comments); err != nil {
+			return err
+		}
+
+		start += len(comments)
+
+		if len(comments) < batchSize {
+			break
+		}
+	}
+
+	return nil
 }