admin speedup: defer big json fields to optimise the admin list page (#38)

The list of objects in django admin doesn't use the big jsons fields, so it's okay to defer them. This makes for a significant speed up as some of the JSONs are a few MB in size, and loading a list of 50 or a 100 (one page) of those objects would mean 100s of MB more data to read from the database that is then not even used.

Author: artcz

intbot/core/admin.py

@@ -87,6 +87,11 @@ class PretalxDataAdmin(admin.ModelAdmin):
         "processed_at",
     ]
 
+    def get_queryset(self, request):
+        qs = super().get_queryset(request)
+        qs = qs.defer("content")
+        return qs
+
     def pretty_content(self, obj: PretalxData):
         return format_html("<pre>{}</pre>", json.dumps(obj.content, indent=4))
 
@@ -113,6 +118,11 @@ class PretixDataAdmin(admin.ModelAdmin):
         "processed_at",
     ]
 
+    def get_queryset(self, request):
+        qs = super().get_queryset(request)
+        qs = qs.defer("content")
+        return qs
+
     def pretty_content(self, obj: PretixData):
         return format_html("<pre>{}</pre>", json.dumps(obj.content, indent=4))