Improve bookmark query performance (#334)

* Remove tag projection from bookmark queries

* add feeds performance test

bookmarks/views/bookmarks.py

@@ -73,8 +73,8 @@ def get_bookmark_view_context(request: WSGIRequest,
     paginator = Paginator(query_set, _default_page_size)
     bookmarks = paginator.get_page(page)
     selected_tags = _get_selected_tags(tags, filters.query)
-    # Prefetch owner relation, this avoids n+1 queries when using the owner in templates
-    prefetch_related_objects(bookmarks.object_list, 'owner')
+    # Prefetch related objects, this avoids n+1 queries when accessing fields in templates
+    prefetch_related_objects(bookmarks.object_list, 'owner', 'tags')
     return_url = generate_return_url(base_url, page, filters)
     link_target = request.user.profile.bookmark_link_target
 

bookmarks/views/settings.py

@@ -5,6 +5,7 @@ from functools import lru_cache
 import requests
 from django.contrib import messages
 from django.contrib.auth.decorators import login_required
+from django.db.models import prefetch_related_objects
 from django.http import HttpResponseRedirect, HttpResponse
 from django.shortcuts import render
 from django.urls import reverse
@@ -114,7 +115,9 @@ def bookmark_import(request):
 def bookmark_export(request):
     # noinspection PyBroadException
     try:
-        bookmarks = query_bookmarks(request.user, '')
+        bookmarks = list(query_bookmarks(request.user, ''))
+        # Prefetch tags to prevent n+1 queries
+        prefetch_related_objects(bookmarks, 'tags')
         file_content = exporter.export_netscape_html(bookmarks)
 
         response = HttpResponse(content_type='text/plain; charset=UTF-8')