diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -763,6 +763,7 @@
     'FeedPublisherWorker' => 'applications/feed/worker/FeedPublisherWorker.php',
     'FeedPushWorker' => 'applications/feed/worker/FeedPushWorker.php',
     'FeedQueryConduitAPIMethod' => 'applications/feed/conduit/FeedQueryConduitAPIMethod.php',
+    'FeedStoryNotificationGarbageCollector' => 'applications/notification/garbagecollector/FeedStoryNotificationGarbageCollector.php',
     'FileAllocateConduitAPIMethod' => 'applications/files/conduit/FileAllocateConduitAPIMethod.php',
     'FileConduitAPIMethod' => 'applications/files/conduit/FileConduitAPIMethod.php',
     'FileCreateMailReceiver' => 'applications/files/mail/FileCreateMailReceiver.php',
@@ -4048,6 +4049,7 @@
     'FeedPublisherWorker' => 'FeedPushWorker',
     'FeedPushWorker' => 'PhabricatorWorker',
     'FeedQueryConduitAPIMethod' => 'FeedConduitAPIMethod',
+    'FeedStoryNotificationGarbageCollector' => 'PhabricatorGarbageCollector',
     'FileAllocateConduitAPIMethod' => 'FileConduitAPIMethod',
     'FileConduitAPIMethod' => 'ConduitAPIMethod',
     'FileCreateMailReceiver' => 'PhabricatorMailReceiver',
diff --git a/src/applications/notification/garbagecollector/FeedStoryNotificationGarbageCollector.php b/src/applications/notification/garbagecollector/FeedStoryNotificationGarbageCollector.php
new file mode 100644
--- /dev/null
+++ b/src/applications/notification/garbagecollector/FeedStoryNotificationGarbageCollector.php
@@ -0,0 +1,22 @@
+<?php
+
+final class FeedStoryNotificationGarbageCollector
+  extends PhabricatorGarbageCollector {
+
+  public function collectGarbage() {
+    $ttl = 90 * 24 * 60 * 60;
+
+    $table = new PhabricatorFeedStoryNotification();
+    $conn_w = $table->establishConnection('w');
+
+    queryfx(
+      $conn_w,
+      'DELETE FROM %T WHERE chronologicalKey < (%d << 32)
+        ORDER BY chronologicalKey ASC LIMIT 100',
+      $table->getTableName(),
+      time() - $ttl);
+
+    return ($conn_w->getAffectedRows() == 100);
+  }
+
+}
diff --git a/src/applications/notification/storage/PhabricatorFeedStoryNotification.php b/src/applications/notification/storage/PhabricatorFeedStoryNotification.php
--- a/src/applications/notification/storage/PhabricatorFeedStoryNotification.php
+++ b/src/applications/notification/storage/PhabricatorFeedStoryNotification.php
@@ -28,6 +28,9 @@
         'key_object' => array(
           'columns' => array('primaryObjectPHID'),
         ),
+        'key_chronological' => array(
+          'columns' => array('chronologicalKey'),
+        ),
       ),
     ) + parent::getConfiguration();
   }