quick hack to optimize finding max valid fa_id

rake/fa.rake

@@ -27,7 +27,8 @@ namespace :fa do
 
     start_at = ENV["start_at"]
     if start_at.is_a?(String) && start_at == "last"
-      start_at = Domain::Post::FaPost.where(state: :ok).maximum(:fa_id) - 1000
+      Domain::Post::FaPost.last
+      start_at = DomainPostsFaAux.where(state: :ok).maximum(:fa_id) - 1000
       start_at = 0 if start_at < 0
       stop_at =
         ENV["stop_at"]&.to_i || GlobalState.get(global_state_key)&.to_i ||

sorbet/rbi/shims/aux.rbi

@@ -0,0 +1,9 @@
+# typed: strict
+
+class DomainPostsFaAux < ActiveRecord::Base
+  extend T::Sig
+
+  sig { returns(T.nilable(Integer)) }
+  def fa_id
+  end
+end