only store a certain percentage of discopane collections (bug 645180)

apps/discovery/views.py

@@ -13,6 +13,7 @@
 
 import commonware.log
 import jingo
+import waffle
 
 import amo
 import amo.utils
@@ -148,6 +149,11 @@ def recommendations(request, version, platform, limit=9):
     recs = _recommendations(request, version, platform, limit,
                             index, ids, recs)
 
+    # We're only storing a percentage of the collections we see because the db
+    # can't keep up with 100%.
+    if not waffle.sample_is_active('disco-pane-store-collections'):
+        return recs
+
     # Users have a token2 if they've been here before. The token matches
     # addon_index in their SyncedCollection.
     if 'token2' in POST:

migrations/179-more-waffles.sql

@@ -0,0 +1,5 @@
+CREATE TABLE `waffle_sample` (
+    `id` integer AUTO_INCREMENT NOT NULL PRIMARY KEY,
+    `name` varchar(100) NOT NULL UNIQUE,
+    `percent` numeric(4, 1) NOT NULL
+) ENGINE=InnoDB CHARACTER SET utf8 COLLATE utf8_general_ci;