diff --git a/app/services/badge_granter.rb b/app/services/badge_granter.rb
index 33d01fc6b..921d228b5 100644
--- a/app/services/badge_granter.rb
+++ b/app/services/badge_granter.rb
@@ -74,7 +74,7 @@ class BadgeGranter
              LEFT JOIN ( #{badge.query} ) q
              ON q.user_id = ub.user_id
               #{post_clause}
-             WHERE ub.id = :id AND q.user_id IS NULL
+             WHERE ub.badge_id = :id AND q.user_id IS NULL
            )"
 
     Badge.exec_sql(sql, id: badge.id)
@@ -83,9 +83,9 @@ class BadgeGranter
             SELECT :id, q.user_id, q.granted_at, -1, #{post_id_field}
             FROM ( #{badge.query} ) q
             LEFT JOIN user_badges ub ON
-              ub.id = :id AND ub.user_id = q.user_id
+              ub.badge_id = :id AND ub.user_id = q.user_id
               #{post_clause}
-            WHERE ub.id IS NULL"
+            WHERE ub.badge_id IS NULL"
 
     Badge.exec_sql(sql, id: badge.id)
 
diff --git a/db/migrate/20140705081453_index_user_badges.rb b/db/migrate/20140705081453_index_user_badges.rb
new file mode 100644
index 000000000..332fc1718
--- /dev/null
+++ b/db/migrate/20140705081453_index_user_badges.rb
@@ -0,0 +1,11 @@
+class IndexUserBadges < ActiveRecord::Migration
+  def change
+    execute 'DELETE FROM user_badges USING user_badges ub2
+             WHERE  user_badges.badge_id = ub2.badge_id AND
+                    user_badges.user_id = ub2.user_id AND
+                    user_badges.post_id IS NOT NULL AND
+                    user_badges.id < ub2.id
+    '
+    add_index :user_badges, [:badge_id, :user_id, :post_id], unique: true, where: 'post_id IS NOT NULL'
+  end
+end
diff --git a/spec/services/badge_granter_spec.rb b/spec/services/badge_granter_spec.rb
index c16f1b378..99588e0e8 100644
--- a/spec/services/badge_granter_spec.rb
+++ b/spec/services/badge_granter_spec.rb
@@ -28,8 +28,10 @@ describe BadgeGranter do
 
     it 'should grant missing badges' do
       post = Fabricate(:post, like_count: 30)
-      BadgeGranter.backfill(Badge.find(Badge::NicePost))
-      BadgeGranter.backfill(Badge.find(Badge::GoodPost))
+      2.times {
+        BadgeGranter.backfill(Badge.find(Badge::NicePost))
+        BadgeGranter.backfill(Badge.find(Badge::GoodPost))
+      }
 
       # TODO add welcome
       post.user.user_badges.pluck(:badge_id).sort.should == [Badge::NicePost,Badge::GoodPost]