1 files changed, 40 insertions, 0 deletions
diff --git a/db/migrate/20170914135630_add_index_for_recent_push_events.rb b/db/migrate/20170914135630_add_index_for_recent_push_events.rb
new file mode 100644
index 00000000000..99f593b0465
--- /dev/null
+++ b/db/migrate/20170914135630_add_index_for_recent_push_events.rb
@@ -0,0 +1,40 @@
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class AddIndexForRecentPushEvents < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index_if_not_present(
+      :merge_requests,
+      [:source_project_id, :source_branch]
+    )
+
+    remove_concurrent_index_if_present(:merge_requests, :source_project_id)
+  end
+
+  def down
+    add_concurrent_index_if_not_present(:merge_requests, :source_project_id)
+
+    remove_concurrent_index_if_present(
+      :merge_requests,
+      [:source_project_id, :source_branch]
+    )
+  end
+
+  def add_concurrent_index_if_not_present(table, columns)
+    return if index_exists?(table, columns)
+
+    add_concurrent_index(table, columns)
+  end
+
+  def remove_concurrent_index_if_present(table, columns)
+    return unless index_exists?(table, columns)
+
+    remove_concurrent_index(table, columns)
+  end
+end