Optimize sorting gallery by Likes/Comments via caching

cmd/nonshy/main.go

@@ -261,6 +261,21 @@ func main() {
 								return err
 							}
 
+							return nil
+						},
+					},
+					{
+						Name:  "photo-counts",
+						Usage: "repopulate cached Likes and Comment counts on photos",
+						Action: func(c *cli.Context) error {
+							initdb(c)
+
+							log.Info("Running BackfillPhotoCounts()")
+							err := backfill.BackfillPhotoCounts()
+							if err != nil {
+								return err
+							}
+
 							return nil
 						},
 					},

pkg/controller/api/likes.go

@@ -204,6 +204,13 @@ func Likes() http.HandlerFunc {
 			}
 		}
 
+		// Refresh cached like counts.
+		if req.TableName == "photos" {
+			if err := models.UpdatePhotoCachedCounts(tableID); err != nil {
+				log.Error("UpdatePhotoCachedCount(%d): %s", tableID, err)
+			}
+		}
+
 		// Send success response.
 		SendJSON(w, http.StatusOK, Response{
 			OK:    true,

pkg/controller/comment/post_comment.go

@@ -121,6 +121,14 @@ func PostComment() http.HandlerFunc {
 							// Log the change.
 							models.LogDeleted(&models.User{ID: comment.UserID}, currentUser, "comments", comment.ID, "Deleted a comment.", comment)
 						}
+
+						// Refresh cached like counts.
+						if tableName == "photos" {
+							if err := models.UpdatePhotoCachedCounts(tableID); err != nil {
+								log.Error("UpdatePhotoCachedCount(%d): %s", tableID, err)
+							}
+						}
+
 						templates.Redirect(w, fromURL)
 						return
 					}
@@ -174,6 +182,13 @@ func PostComment() http.HandlerFunc {
 					session.Flash(w, r, "Comment added!")
 					templates.Redirect(w, fromURL)
 
+					// Refresh cached comment counts.
+					if tableName == "photos" {
+						if err := models.UpdatePhotoCachedCounts(tableID); err != nil {
+							log.Error("UpdatePhotoCachedCount(%d): %s", tableID, err)
+						}
+					}
+
 					// Log the change.
 					models.LogCreated(currentUser, "comments", comment.ID, "Posted a new comment.\n\n---\n\n"+message)
 

pkg/controller/photo/site_gallery.go

@@ -18,10 +18,8 @@ func SiteGallery() http.HandlerFunc {
 	var sortWhitelist = []string{
 		"created_at desc",
 		"created_at asc",
-
-		// Custom (advanced) sort options.
-		"by_likes",
-		"by_comments",
+		"like_count desc",
+		"comment_count desc",
 	}
 
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {

pkg/controller/photo/user_gallery.go

@@ -19,10 +19,8 @@ func UserPhotos() http.HandlerFunc {
 		"pinned desc nulls last, updated_at desc",
 		"created_at desc",
 		"created_at asc",
-
-		// Custom (advanced) sort options.
-		"by_likes",
-		"by_comments",
+		"like_count desc",
+		"comment_count desc",
 	}
 
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {

pkg/models/backfill/backfill_photo_counts.go

@@ -0,0 +1,25 @@
+package backfill
+
+import (
+	"code.nonshy.com/nonshy/website/pkg/models"
+)
+
+// BackfillPhotoCounts recomputes the cached Likes and Comment counts on photos.
+func BackfillPhotoCounts() error {
+	res := models.DB.Exec(`
+		UPDATE photos
+		SET like_count = (
+			SELECT count(id)
+			FROM likes
+			WHERE table_name='photos'
+			AND table_id=photos.id
+		),
+		comment_count = (
+			SELECT count(id)
+			FROM comments
+			WHERE table_name='photos'
+			AND table_id=photos.id
+		);
+	`)
+	return res.Error
+}

pkg/models/photo.go

@@ -25,6 +25,8 @@ type Photo struct {
 	Gallery         bool            `gorm:"index"` // photo appears in the public gallery (if public)
 	Explicit        bool            `gorm:"index"` // is an explicit photo
 	Pinned          bool            `gorm:"index"` // user pins it to the front of their gallery
+	LikeCount       int64           `gorm:"index"` // cache of 'likes' count
+	CommentCount    int64           `gorm:"index"` // cache of comments count
 	CreatedAt       time.Time       `gorm:"index"`
 	UpdatedAt       time.Time
 }
@@ -135,24 +137,6 @@ func PaginateUserPhotos(userID uint64, conf UserGallery, pager *Pagination) ([]*
 		placeholders = append(placeholders, explicit[0])
 	}
 
-	// Custom SORT parameters.
-	switch pager.Sort {
-	case "by_likes":
-		pager.Sort = `(
-			SELECT count(likes.id)
-			FROM likes
-			WHERE likes.table_name = 'photos'
-			AND likes.table_id = photos.id
-		) DESC`
-	case "by_comments":
-		pager.Sort = `(
-			SELECT count(comments.id)
-			FROM comments
-			WHERE comments.table_name = 'photos'
-			AND comments.table_id = photos.id
-		) DESC NULLS LAST`
-	}
-
 	query := DB.Where(
 		strings.Join(wheres, " AND "),
 		placeholders...,
@@ -690,38 +674,33 @@ func PaginateGalleryPhotos(user *User, conf Gallery, pager *Pagination) ([]*Phot
 		)
 	}
 
-	// Get count pre-sorting.
-	query.Model(&Photo{}).Count(&pager.Total)
-
-	// Custom SORT parameters.
-	switch pager.Sort {
-	case "by_likes":
-		query = query.Select(`
-			photos.*,
-			COUNT(likes.id) AS like_count
-		`).Joins(
-			"LEFT OUTER JOIN likes ON (likes.table_name='photos' AND likes.table_id=photos.id)",
-		).Where(
-			"likes.table_name = 'photos' AND likes.table_id = photos.id",
-		).Group("photos.id")
-		pager.Sort = `like_count DESC`
-	case "by_comments":
-		query = query.Select(`
-			photos.*,
-			COUNT(comments.id) AS comment_count
-		`).Joins(
-			"LEFT OUTER JOIN comments ON (comments.table_name='photos' AND comments.table_id=photos.id)",
-		).Where(
-			"comments.table_name = 'photos' AND comments.table_id = photos.id",
-		).Group("photos.id")
-		pager.Sort = `comment_count DESC`
-	}
-
 	query = query.Order(pager.Sort)
+	query.Model(&Photo{}).Count(&pager.Total)
 	result := query.Offset(pager.GetOffset()).Limit(pager.PerPage).Find(&p)
 	return p, result.Error
 }
 
+// UpdatePhotoCachedCounts will refresh the cached like/comment count on the photos table.
+func UpdatePhotoCachedCounts(photoID uint64) error {
+	res := DB.Exec(`
+		UPDATE photos
+		SET like_count = (
+			SELECT count(id)
+			FROM likes
+			WHERE table_name='photos'
+			AND table_id=photos.id
+		),
+		comment_count = (
+			SELECT count(id)
+			FROM comments
+			WHERE table_name='photos'
+			AND table_id=photos.id
+		)
+		WHERE photos.id = ?;
+	`, photoID)
+	return res.Error
+}
+
 // Save photo.
 func (p *Photo) Save() error {
 	result := DB.Save(p)

web/templates/photo/gallery.html

@@ -414,8 +414,8 @@
                                             {{end}}
                                             <option value="created_at desc"{{if eq .Sort "created_at desc"}} selected{{end}}>Most recent</option>
                                             <option value="created_at asc"{{if eq .Sort "created_at asc"}} selected{{end}}>Oldest first</option>
-                                            <option value="by_likes"{{if eq .Sort "by_likes"}} selected{{end}}>Most likes</option>
-                                            <option value="by_comments"{{if eq .Sort "by_comments"}} selected{{end}}>Most comments</option>
+                                            <option value="like_count desc"{{if eq .Sort "like_count desc"}} selected{{end}}>Most likes</option>
+                                            <option value="comment_count desc"{{if eq .Sort "comment_count desc"}} selected{{end}}>Most comments</option>
                                         </select>
                                     </div>
                                 </div>