Improve batch size

app/models/concerns/issuable_states.rb

@@ -2,7 +2,7 @@
 
 # == IssuableStates concern
 #
-# Defines statuses shared by issuables which are persisted on state column
+# Defines states shared by issuables which are persisted on state_id column
 # using the state machine.
 #
 # Used by EE::Epic, Issue and MergeRequest
@@ -14,10 +14,6 @@ module IssuableStates
   # Check MergeRequest::AVAILABLE_STATES
   AVAILABLE_STATES = { opened: 1, closed: 2 }.freeze
 
-  included do
-    before_save :set_state_id
-  end
-
   class_methods do
     def states
       @states ||= OpenStruct.new(self::AVAILABLE_STATES)
@@ -26,7 +22,11 @@ module IssuableStates
 
   # The state:string column is being migrated to state_id:integer column
   # This is a temporary hook to populate state_id column with new values
-  # and can be removed after the complete migration is done.
+  # and can be removed after the state column is removed.
+  included do
+    before_save :set_state_id
+  end
+
   def set_state_id
     return if state.nil? || state.empty?
 

app/models/merge_request.rb

@@ -22,7 +22,6 @@ class MergeRequest < ActiveRecord::Base
   self.reactive_cache_lifetime = 10.minutes
 
   SORTING_PREFERENCE_FIELD = :merge_requests_sort
-  MERGE_REQUEST_STATES =
   AVAILABLE_STATES = AVAILABLE_STATES.merge(merged: 3, locked: 4).freeze
 
   ignore_column :locked_at,

db/migrate/20190211131150_add_state_id_to_issuables.rb

@@ -5,10 +5,12 @@ class AddStateIdToIssuables < ActiveRecord::Migration[5.0]
   DOWNTIME = false
   MIGRATION = 'SyncIssuablesStateId'.freeze
 
-  # TODO - find out how many issues and merge requests in production
-  # to adapt the batch size and delay interval
-  # Keep in mind that the migration will be scheduled for issues and merge requests.
-  BATCH_SIZE = 5000
+  # 2019-02-12 Gitlab.com issuable numbers
+  # issues count: 13587305
+  # merge requests count: 18925274
+  # Using this 50000 as batch size should take around 13 hours
+  # to migrate both issues and merge requests
+  BATCH_SIZE = 50000
   DELAY_INTERVAL = 5.minutes.to_i
 
   class Issue < ActiveRecord::Base