diff --git a/lib/core_ext/active_record/connection_adapters/cockroachdb/lock.rb b/lib/core_ext/active_record/connection_adapters/cockroachdb/lock.rb
new file mode 100644
index 000000000000..f95cba0f0ced
--- /dev/null
+++ b/lib/core_ext/active_record/connection_adapters/cockroachdb/lock.rb
@@ -0,0 +1,12 @@
+# Cockroachdb does not implement the locking of select...for update.
+# but, it doesn't need it since it uses serialised updates. So
+# we make it a no-op
+# https://github.com/cockroachdb/activerecord-cockroachdb-adapter/issues/21
+module ActiveRecord
+  class Base
+    def lock!(lock = true)
+      super(lock) unless self.class.connection.class.to_s == 'ActiveRecord::ConnectionAdapters::CockroachDBAdapter'
+    end
+  end
+end
+