Use repeatable read for commitfest and dashboard query

Author: JelteF

pgcommitfest/commitfest/views.py

@@ -88,7 +88,13 @@ def help(request):
 
 
 @login_required
+@transaction.atomic
 def me(request):
+    curs = connection.cursor()
+    # Make sure the patchlist() query, the stats query and, Tag.objects.all()
+    # all work on the same snapshot. Needs to be first in the
+    # transaction.atomic decorator.
+    curs.execute("SET TRANSACTION ISOLATION LEVEL REPEATABLE READ")
     cfs = list(CommitFest.objects.filter(status=CommitFest.STATUS_INPROGRESS))
     if len(cfs) == 0:
         cfs = list(CommitFest.objects.filter(status=CommitFest.STATUS_OPEN))
@@ -108,7 +114,6 @@ def me(request):
         return patch_list.redirect
 
     # Get stats related to user for current commitfest
-    curs = connection.cursor()
     curs.execute(
         """SELECT
             ps.status, ps.statusstring, count(*)
@@ -290,8 +295,9 @@ def patchlist(request, cf, personalized=False):
             tag_ids = [int(t) for t in request.GET.getlist("tag")]
             for tag_id in tag_ids:
                 # Instead of using parameters, we just inline the tag_id. This
-                # is easier, and since tag_id is always an int it's safe with
-                # respect to SQL injection.
+                # is easier because we have can have multiple tags, and since
+                # tag_id is always an int it's safe with respect to SQL
+                # injection.
                 whereclauses.append(
                     f"EXISTS (SELECT 1 FROM commitfest_patch_tags tags WHERE tags.patch_id=p.id AND tags.tag_id={tag_id})"
                 )
@@ -569,8 +575,13 @@ def patchlist(request, cf, personalized=False):
     )
 
 
-@transaction.atomic  # tie the patchlist() query to Tag.objects.all()
+@transaction.atomic
 def commitfest(request, cfid):
+    curs = connection.cursor()
+    # Make sure the patchlist() query, the stats query and, Tag.objects.all()
+    # all work on the same snapshot. Needs to be first in the
+    # transaction.atomic decorator.
+    curs.execute("SET TRANSACTION ISOLATION LEVEL REPEATABLE READ")
     # Find ourselves
     cf = get_object_or_404(CommitFest, pk=cfid)
 
@@ -579,7 +590,6 @@ def commitfest(request, cfid):
         return patch_list.redirect
 
     # Generate patch status summary.
-    curs = connection.cursor()
     curs.execute(
         "SELECT ps.status, ps.statusstring, count(*) FROM commitfest_patchoncommitfest poc INNER JOIN commitfest_patchstatus ps ON ps.status=poc.status WHERE commitfest_id=%(id)s GROUP BY ps.status ORDER BY ps.sortkey",
         {