perf: batch label stats query + fix scoped thumb

sidecar/handlers_labels.go

@@ -57,29 +57,52 @@ func handleLabels(pp *ppClient, ppDb *gorm.DB) gin.HandlerFunc {
 			return
 		}
 
-		// For each label, count how many photos under this user's BasePath
-		// have that label. Remove labels with zero count for this user.
-		filtered := make([]PpLabel, 0, len(labels))
+		// One query: count + a representative scoped thumb for every label
+		// the user can see. Replaces N per-label queries with a single JOIN.
 		prefix := basePath + "/%"
 
+		type labelStat struct {
+			LabelUID  string `gorm:"column:label_uid"`
+			Cnt       int64  `gorm:"column:cnt"`
+			ThumbHash string `gorm:"column:thumb_hash"`
+		}
+		var stats []labelStat
+		if err := ppDb.Raw(`
+			SELECT lb.label_uid                          AS label_uid,
+			       COUNT(DISTINCT p.id)                  AS cnt,
+			       COALESCE(MIN(f.file_hash), '')        AS thumb_hash
+			FROM   photos_labels pl
+			JOIN   photos p  ON pl.photo_id  = p.id
+			JOIN   labels lb ON pl.label_id  = lb.id
+			LEFT JOIN files f ON f.photo_uid   = p.photo_uid
+			                 AND f.file_primary = 1
+			                 AND f.file_missing = 0
+			WHERE  (p.photo_path = ? OR p.photo_path LIKE ?)
+			  AND  p.deleted_at IS NULL
+			GROUP  BY lb.label_uid
+			HAVING cnt > 0
+		`, basePath, prefix).Scan(&stats).Error; err != nil {
+			c.JSON(http.StatusBadGateway, gin.H{"error": "label stats query failed"})
+			return
+		}
+
+		cntMap := make(map[string]int64, len(stats))
+		thumbMap := make(map[string]string, len(stats))
+		for _, s := range stats {
+			cntMap[s.LabelUID] = s.Cnt
+			thumbMap[s.LabelUID] = s.ThumbHash
+		}
+
+		filtered := make([]PpLabel, 0, len(stats))
 		for _, l := range labels {
-			var cnt int64
-			if err := ppDb.Raw(
-				`SELECT COUNT(*) FROM photos_labels pl
-				 JOIN photos p ON pl.photo_id = p.id
-				 JOIN labels lb ON pl.label_id = lb.id
-				 WHERE lb.label_uid = ?
-				   AND (p.photo_path = ? OR p.photo_path LIKE ?)
-				   AND p.deleted_at IS NULL`,
-				l.UID, basePath, prefix,
-			).Count(&cnt).Error; err != nil {
-				// On DB error, skip this label rather than failing the whole response.
-				continue
-			}
-			if cnt == 0 {
+			cnt, ok := cntMap[l.UID]
+			if !ok || cnt == 0 {
 				continue
 			}
 			l.PhotoCount = int(cnt)
+			if th := thumbMap[l.UID]; th != "" {
+				l.Thumb = th
+			}
 			filtered = append(filtered, l)
 		}
 

web/src/lib/services/photoprism.ts

@@ -713,7 +713,9 @@ export async function listLabels(): Promise<PpLabel[]> {
 	const { data } = await sidecar.get<PpLabel[]>('/api/sidecar/labels', {
 		params: { count: 1000, order: 'count', all: true, perPage: 1000 }
 	});
-	return filterByUserPhotos(data, (l) => `label:${l.Slug}`);
+	// Sidecar already filters to the user's scope and sets correct counts +
+	// thumbs in one DB query — no need to probe each label individually.
+	return data;
 }
 
 // ── Subjects (people / face recognition) ────────────────────────────────────