Force with_fast_statement_timeout to use replicas

app/models/application_record.rb

@@ -52,13 +52,15 @@ class ApplicationRecord < ActiveRecord::Base
 
   # Start a new transaction with a shorter-than-usual statement timeout. This is
   # currently one third of the default 15-second timeout
-  def self.with_fast_statement_timeout
+  def self.with_fast_read_statement_timeout
+    ::Gitlab::Database::LoadBalancing::Session.current.use_replica do
       transaction(requires_new: true) do
         connection.exec_query("SET LOCAL statement_timeout = 5000")
 
         yield
       end
     end
+  end
 
   def self.safe_find_or_create_by(*args, &block)
     safe_ensure_unique(retries: 1) do

lib/gitlab/issuables_count_for_state.rb

@@ -78,7 +78,7 @@ module Gitlab
       # to perform the calculation more efficiently. Until then, use a shorter
       # timeout and return -1 as a sentinel value if it is triggered
       begin
-        ApplicationRecord.with_fast_statement_timeout do
+        ApplicationRecord.with_fast_read_statement_timeout do
           finder.count_by_state
         end
       rescue ActiveRecord::QueryCanceled => err