optimise some dicom manipulations

atlas/api.py

@@ -357,36 +357,38 @@ def series_split_by_tag(request, series_id: int, dicom_tag: str):
 
     image_map = defaultdict(list)
 
-    # Split teh associated images
-    for image in series.images.all():
+    # Use iterator to avoid loading all images into memory
+    for image in series.images.iterator():
         ds = image.get_dicom_data()
-
         if dicom_tag in ds:
             val = ds[dicom_tag].value
-
-            if type(val) == pydicom.multival.MultiValue:
-                image_map[",".join((val))].append(image)
+            if isinstance(val, pydicom.multival.MultiValue):
+                key = ",".join(map(str, val))
             else:
-                image_map[val].append(image)
+                key = str(val)
+            image_map[key].append(image)
         else:
             return [f"{dicom_tag} not found {image}"]
 
+    case = list(series.case.all())
+    authors = list(series.author.all())
     new_series = []
-    case = series.case.all()
-    authors = series.author.all()
 
-    for n, option in enumerate(image_map):
-        if n == 0:
-            series.images.set(image_map[option])
-
-        else:
-            series.pk = None
-            series.save()
-            series.case.set(case)
-            series.author.set(authors)
-            series.images.set(image_map[option])
-
-        new_series.append(series.pk)
+    # Use a transaction for all DB changes
+    with transaction.atomic():
+        for n, (option, images) in enumerate(image_map.items()):
+            if n == 0:
+                # Update the original series
+                series.images.set(images)
+                new_series.append(series.pk)
+            else:
+                # Clone the series
+                series.pk = None
+                series.save()
+                series.case.set(case)
+                series.author.set(authors)
+                series.images.set(images)
+                new_series.append(series.pk)
 
     return new_series