Fix most unnecessary database queries in huddle creation.

This saves 2 database queries per user in the huddle when sending the
first message to a particular huddle.

(imported from commit f71aa32df846fb4b82651a93ff9608087ffcaa5a)

zephyr/lib/actions.py

@@ -4,7 +4,8 @@ from zephyr.lib.context_managers import lockfile
 from zephyr.models import Realm, Stream, UserProfile, UserActivity, \
     Subscription, Recipient, Message, UserMessage, valid_stream_name, \
     DefaultStream, StreamColor, UserPresence, MAX_SUBJECT_LENGTH, \
-    MAX_MESSAGE_LENGTH, get_client, get_stream, get_recipient, get_huddle
+    MAX_MESSAGE_LENGTH, get_client, get_stream, get_recipient, get_huddle, \
+    get_user_profile_by_id
 from django.db import transaction, IntegrityError
 from django.db.models import F
 from django.core.exceptions import ValidationError
@@ -130,10 +131,6 @@ def log_message(message):
     if not message.sending_client.name.startswith("test:"):
         log_event(message.to_log_dict())
 
-@cache_with_key(user_profile_by_id_cache_key)
-def get_user_profile_by_id(uid):
-    return UserProfile.objects.select_related().get(id=uid)
-
 def do_send_message(message, rendered_content=None, no_log=False,
                     stream=None):
     # Log the message to our message log for populate_db to refill

zephyr/lib/cache.py

@@ -88,4 +88,3 @@ def update_user_cache(sender, **kwargs):
     items_for_memcached = {}
     items_for_memcached[user_by_id_cache_key(user.id)] = (user,)
     djcache.set_many(items_for_memcached)
-

zephyr/management/commands/populate_db.py

@@ -5,9 +5,8 @@ from django.contrib.auth.models import User
 from django.contrib.sites.models import Site
 from zephyr.models import Message, UserProfile, Stream, Recipient, Client, \
     Subscription, Huddle, get_huddle, Realm, UserMessage, StreamColor, \
-    get_huddle_hash, clear_database, get_client
-from zephyr.lib.actions import get_user_profile_by_id, \
-    do_send_message, set_default_streams, do_activate_user
+    get_huddle_hash, clear_database, get_client, get_user_profile_by_id
+from zephyr.lib.actions import do_send_message, set_default_streams, do_activate_user
 from zephyr.lib.parallel import run_parallel
 from django.db import transaction, connection
 from django.conf import settings

zephyr/models.py

@@ -2,7 +2,7 @@ from django.db import models
 from django.conf import settings
 from django.contrib.auth.models import User
 from zephyr.lib.cache import cache_with_key, update_user_profile_cache, \
-    update_user_cache
+    update_user_cache, user_profile_by_id_cache_key
 from zephyr.lib.initial_password import initial_api_key
 from zephyr.lib.utils import make_safe_digest
 import os
@@ -332,6 +332,10 @@ class Subscription(models.Model):
     def __str__(self):
         return self.__repr__()
 
+@cache_with_key(user_profile_by_id_cache_key)
+def get_user_profile_by_id(uid):
+    return UserProfile.objects.select_related().get(id=uid)
+
 class Huddle(models.Model):
     # TODO: We should consider whether using
     # CommaSeparatedIntegerField would be better.
@@ -353,12 +357,13 @@ def get_huddle(id_list):
 def get_huddle_backend(huddle_hash, id_list):
     (huddle, created) = Huddle.objects.get_or_create(huddle_hash=huddle_hash)
     if created:
-        recipient = Recipient.objects.create(type_id=huddle.id,
-                                             type=Recipient.HUDDLE)
-        # Add subscriptions
-        for uid in id_list:
-            Subscription.objects.create(recipient = recipient,
-                                        user_profile = UserProfile.objects.get(id=uid))
+        with transaction.commit_on_success():
+            recipient = Recipient.objects.create(type_id=huddle.id,
+                                                 type=Recipient.HUDDLE)
+            subs_to_create = [Subscription(recipient=recipient,
+                                           user_profile=get_user_profile_by_id(user_profile_id))
+                              for user_profile_id in id_list]
+            Subscription.objects.bulk_create(subs_to_create)
     return huddle
 
 # This function is used only by tests.