diff --git a/zerver/lib/actions.py b/zerver/lib/actions.py
index 4047c126d7..4162b0e1e4 100644
--- a/zerver/lib/actions.py
+++ b/zerver/lib/actions.py
@@ -196,7 +196,6 @@ def compute_mit_user_fullname(email):
 
 @cache_with_key(lambda realm, email, f: user_profile_by_email_cache_key(email),
                 timeout=3600*24*7)
-@transaction.commit_on_success
 def create_mirror_user_if_needed(realm, email, email_to_fullname):
     try:
         return get_user_profile_by_email(email)
@@ -207,9 +206,6 @@ def create_mirror_user_if_needed(realm, email, email_to_fullname):
                                email_to_fullname(email), email_to_username(email),
                                active=False)
         except IntegrityError:
-            # Unless we raced with another thread doing the same
-            # thing, in which case we should get the user they made
-            transaction.commit()
             return get_user_profile_by_email(email)
 
 def log_message(message):
@@ -1249,19 +1245,13 @@ def do_update_user_activity_interval(user_profile, log_time):
                                         end=effective_end)
 
 @statsd_increment('user_activity')
-@transaction.commit_on_success
 def do_update_user_activity(user_profile, client, query, log_time):
-    try:
-        (activity, created) = UserActivity.objects.get_or_create(
-            user_profile = user_profile,
-            client = client,
-            query = query,
-            defaults={'last_visit': log_time, 'count': 0})
-    except IntegrityError:
-        transaction.commit()
-        activity = UserActivity.objects.get(user_profile = user_profile,
-                                            client = client,
-                                            query = query)
+    (activity, created) = UserActivity.objects.get_or_create(
+        user_profile = user_profile,
+        client = client,
+        query = query,
+        defaults={'last_visit': log_time, 'count': 0})
+
     activity.count += 1
     activity.last_visit = log_time
     activity.save(update_fields=["last_visit", "count"])
@@ -1275,19 +1265,12 @@ def send_presence_changed(user_profile, presence):
     tornado_callbacks.send_notification(notice)
 
 @statsd_increment('user_presence')
-@transaction.commit_on_success
 def do_update_user_presence(user_profile, client, log_time, status):
-    try:
-        (presence, created) = UserPresence.objects.get_or_create(
-            user_profile = user_profile,
-            client = client,
-            defaults = {'timestamp': log_time,
-                        'status': status})
-    except IntegrityError:
-        transaction.commit()
-        presence = UserPresence.objects.get(user_profile = user_profile,
-                                            client = client)
-        created = False
+    (presence, created) = UserPresence.objects.get_or_create(
+        user_profile = user_profile,
+        client = client,
+        defaults = {'timestamp': log_time,
+                    'status': status})
 
     stale_status = (log_time - presence.timestamp) > datetime.timedelta(minutes=1, seconds=10)
     was_idle = presence.status == UserPresence.IDLE
diff --git a/zerver/worker/queue_processors.py b/zerver/worker/queue_processors.py
index e4909f68f7..91355b8aee 100644
--- a/zerver/worker/queue_processors.py
+++ b/zerver/worker/queue_processors.py
@@ -1,6 +1,5 @@
 from __future__ import absolute_import
 
-from django.db.transaction import commit_on_success
 from django.conf import settings
 from postmonkey import PostMonkey, MailChimpException
 from zerver.models import UserActivityInterval, get_user_profile_by_email, \
@@ -50,8 +49,7 @@ class QueueProcessingWorker(object):
 
     def consume_wrapper(self, data):
         try:
-            with commit_on_success():
-                self.consume(data)
+            self.consume(data)
         except Exception:
             self._log_problem()
             if not os.path.exists(settings.QUEUE_ERROR_DIR):
@@ -180,8 +178,7 @@ class MissedMessageWorker(QueueProcessingWorker):
                 by_recipient[event['user_profile_id']].append(event)
 
             for user_profile_id, events in by_recipient.items():
-                with commit_on_success():
-                    handle_missedmessage_emails(user_profile_id, events)
+                handle_missedmessage_emails(user_profile_id, events)
 
             # Aggregate all messages received every 2 minutes to let someone finish sending a batch
             # of messages
@@ -225,8 +222,7 @@ class SlowQueryWorker(QueueProcessingWorker):
                 for query in slow_queries:
                     content += "    %s\n" % (query,)
 
-                with commit_on_success():
-                    internal_send_message(settings.ERROR_BOT, "stream", "logs", topic, content)
+                internal_send_message(settings.ERROR_BOT, "stream", "logs", topic, content)
 
             # Aggregate all slow query messages in 1-minute chunks to avoid message spam
             time.sleep(1 * 60)