diff --git a/update.md b/update.md
index 064d53f212..e3d0166a45 100644
--- a/update.md
+++ b/update.md
@@ -512,6 +512,8 @@ Notifications
 1. Lors de l'application des migrations `python manage.py migrate`, Django va vous demander s'il doit supprimer la table topicfollowed. Renseignez oui.
 2. Exécuter la commande `python manage.py migrate_subscriptions` pour migrer les anciennes notifications vers les nouvelles.
 
+Si vous constatez des problèmes de performance, lancez la commande suivante : `mysqloptimize -uroot -p zdsdb`
+
 Liste des tags exclus
 ---------------------
 
diff --git a/zds/notification/migrations/0008_auto_20160507_1504.py b/zds/notification/migrations/0008_auto_20160507_1504.py
new file mode 100644
index 0000000000..192322aa4b
--- /dev/null
+++ b/zds/notification/migrations/0008_auto_20160507_1504.py
@@ -0,0 +1,24 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('notification', '0007_auto_20160121_2343'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='notification',
+            name='object_id',
+            field=models.PositiveIntegerField(db_index=True),
+        ),
+        migrations.AlterField(
+            model_name='subscription',
+            name='object_id',
+            field=models.PositiveIntegerField(db_index=True),
+        ),
+    ]
diff --git a/zds/notification/models.py b/zds/notification/models.py
index 381f50faa7..5cf2d8ed1f 100644
--- a/zds/notification/models.py
+++ b/zds/notification/models.py
@@ -30,7 +30,7 @@ class Meta:
     is_active = models.BooleanField(_(u'Actif'), default=True, db_index=True)
     by_email = models.BooleanField(_(u'Recevoir un email'), default=False)
     content_type = models.ForeignKey(ContentType)
-    object_id = models.PositiveIntegerField()
+    object_id = models.PositiveIntegerField(db_index=True)
     content_object = GenericForeignKey('content_type', 'object_id')
     last_notification = models.ForeignKey(u'Notification', related_name="last_notification", null=True, default=None)
 
@@ -267,7 +267,7 @@ class Meta:
     subscription = models.ForeignKey(Subscription, related_name='subscription', db_index=True)
     pubdate = models.DateTimeField(_(u'Date de création'), auto_now_add=True, db_index=True)
     content_type = models.ForeignKey(ContentType)
-    object_id = models.PositiveIntegerField()
+    object_id = models.PositiveIntegerField(db_index=True)
     content_object = GenericForeignKey('content_type', 'object_id')
     is_read = models.BooleanField(_(u'Lue'), default=False, db_index=True)
     url = models.CharField('URL', max_length=255)