Merge branch 'ab-count-pending-mirror-updates' into 'master'

Add index to count pending mirror updates

Closes gitlab-ce#62419

See merge request gitlab-org/gitlab-ee!13901

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20190530154715) do
+ActiveRecord::Schema.define(version: 20190603124955) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -2454,6 +2454,7 @@ ActiveRecord::Schema.define(version: 20190530154715) do
     t.datetime_with_timezone "last_successful_update_at"
     t.index ["jid"], name: "index_project_mirror_data_on_jid", using: :btree
     t.index ["last_successful_update_at"], name: "index_project_mirror_data_on_last_successful_update_at", using: :btree
+    t.index ["last_update_at", "retry_count"], name: "index_project_mirror_data_on_last_update_at_and_retry_count", using: :btree
     t.index ["next_execution_timestamp", "retry_count"], name: "index_mirror_data_on_next_execution_and_retry_count", using: :btree
     t.index ["project_id"], name: "index_project_mirror_data_on_project_id", unique: true, using: :btree
     t.index ["status"], name: "index_project_mirror_data_on_status", using: :btree

ee/changelogs/unreleased/ab-count-pending-mirror-updates.yml

+---
+title: Add index to count pending mirror updates
+merge_request: 13901
+author:
+type: performance

ee/db/migrate/20190603124955_add_index_to_count_pending_mirror_updates.rb

+# frozen_string_literal: true
+
+class AddIndexToCountPendingMirrorUpdates < ActiveRecord::Migration[5.1]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index :project_mirror_data, [:last_update_at, :retry_count]
+  end
+
+  def down
+    remove_concurrent_index :project_mirror_data, [:last_update_at, :retry_count]
+  end
+end