feat: Optimize image hash checks with bulk queries and add database indexing for performance

atlas/api.py

@@ -583,41 +583,57 @@ def check_image_hash(request, hash: str):
 
 @router.post("/check_image_hashes/", auth=TokenAuth())
 def check_images_hashes(request, hashes: List[str]):
-    """Checks a list of image hashes and returns the series id / url if found
+    """Checks a list of image hashes and returns the series id / url if found.
+
+    Uses two bulk queries (one for SeriesImage, one for UncategorisedDicom) to
+    handle large batches efficiently regardless of batch size.
 
     Return format
     { "hash_id": {"id": "series_id|false", "url": "series_url|false"}, ...}
     """
 
     try:
-        hash_status = {}
+        hash_status: dict = {h: {"id": False, "url": False} for h in hashes}
 
-        for hash in hashes:
-            # Prefer filter().first() to avoid MultipleObjectsReturned
-            series_image = SeriesImage.objects.filter(image_blake3_hash=hash).select_related("series").first()
-            if series_image:
-                try:
-                    url = series_image.series.get_absolute_url()
-                except Exception:
-                    url = None
-                data = {"id": series_image.pk, "url": url, "type": "series"}
-                hash_status[hash] = data
-                continue
+        # Single bulk query for all SeriesImage matches
+        series_images = (
+            SeriesImage.objects.filter(image_blake3_hash__in=hashes)
+            .select_related("series")
+            .only("pk", "image_blake3_hash", "series__slug", "series__pk")
+        )
+        matched_hashes: set = set()
+        for si in series_images:
+            if si.image_blake3_hash in matched_hashes:
+                continue  # keep first match per hash
+            try:
+                url = si.series.get_absolute_url()
+            except Exception:
+                url = None
+            hash_status[si.image_blake3_hash] = {"id": si.pk, "url": url, "type": "series"}
+            matched_hashes.add(si.image_blake3_hash)
 
-            uncategorised = UncategorisedDicom.objects.filter(image_blake3_hash=hash).first()
-            if uncategorised:
-                try:
-                    uploads_url = reverse("atlas:user_uploads")
-                except Exception:
-                    uploads_url = None
-                data = {"id": uncategorised.pk, "url": uploads_url, "type": "uncategorised"}
-                hash_status[hash] = data
-                continue
-
-            hash_status[hash] = {"id": False, "url": False}
+        # Single bulk query for remaining hashes in UncategorisedDicom
+        remaining = [h for h in hashes if h not in matched_hashes]
+        if remaining:
+            try:
+                uploads_url = reverse("atlas:user_uploads")
+            except Exception:
+                uploads_url = None
+            uncategorised_qs = (
+                UncategorisedDicom.objects.filter(image_blake3_hash__in=remaining)
+                .only("pk", "image_blake3_hash")
+            )
+            for uc in uncategorised_qs:
+                if uc.image_blake3_hash not in matched_hashes:
+                    hash_status[uc.image_blake3_hash] = {
+                        "id": uc.pk,
+                        "url": uploads_url,
+                        "type": "uncategorised",
+                    }
+                    matched_hashes.add(uc.image_blake3_hash)
 
         return hash_status
-    except Exception as e:
+    except Exception:
         logger.exception("check_images_hashes failed")
         return JsonResponse({"detail": "Internal server error"}, status=500)