Remove redundant ci_builds partial index on GitLab.com

db/migrate/20181121101843_remove_redundant_ci_builds_partial_index.rb

+# frozen_string_literal: true
+
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class RemoveRedundantCiBuildsPartialIndex < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    remove_concurrent_index(*index_arguments)
+  end
+
+  def down
+    add_concurrent_index(*index_arguments)
+  end
+
+  private
+
+  def index_arguments
+    [
+      :ci_builds,
+      [:project_id, :status],
+      {
+        name: 'index_ci_builds_project_id_and_status_for_live_jobs_partial',
+        where: "((status)::text = ANY (ARRAY[('running'::character varying)::text, ('pending'::character varying)::text, ('created'::character varying)::text]))"
+      }
+    ]
+  end
+end