Add indices for created_at+id and contacted_at+id on ci_runners

Changelog: changed

db/migrate/20210601125410_add_runners_created_at_index.rb

+# frozen_string_literal: true
+
+# See https://docs.gitlab.com/ee/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class AddRunnersCreatedAtIndex < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  disable_ddl_transaction!
+
+  INDEX_NAME = 'index_ci_runners_on_created_at_and_id'
+
+  def up
+    add_concurrent_index :ci_runners, [:created_at, :id], name: INDEX_NAME
+  end
+
+  def down
+    remove_concurrent_index :ci_runners, [:created_at, :id], name: INDEX_NAME
+  end
+end

db/migrate/20210601133459_replace_runners_contacted_at_index.rb

+# frozen_string_literal: true
+
+# See https://docs.gitlab.com/ee/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class ReplaceRunnersContactedAtIndex < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  disable_ddl_transaction!
+
+  OLD_INDEX_NAME = 'index_ci_runners_on_contacted_at'
+  NEW_INDEX_NAME = 'index_ci_runners_on_contacted_at_and_id'
+
+  def up
+    add_concurrent_index :ci_runners, [:contacted_at, :id], name: NEW_INDEX_NAME, using: 'btree'
+
+    remove_concurrent_index_by_name :ci_runners, OLD_INDEX_NAME
+  end
+
+  def down
+    remove_concurrent_index_by_name :ci_runners, NEW_INDEX_NAME
+
+    add_concurrent_index :ci_runners, :contacted_at, name: OLD_INDEX_NAME, using: 'btree'
+  end
+end

db/schema_migrations/20210601125410

+fc500e4dd555a6baad91ad3c9fb8a2f8541e1613dd64afdbdd28b19447a28caf
\ No newline at end of file

db/schema_migrations/20210601133459

+4dcf6277439e8abe52534540100fa621fedcecb3eaf71ad5685ac0230cd2e5bb
\ No newline at end of file

db/structure.sql

@@ -22904,7 +22904,9 @@ CREATE INDEX index_ci_runner_projects_on_project_id ON ci_runner_projects USING
 
 CREATE INDEX index_ci_runner_projects_on_runner_id ON ci_runner_projects USING btree (runner_id);
 
-CREATE INDEX index_ci_runners_on_contacted_at ON ci_runners USING btree (contacted_at);
+CREATE INDEX index_ci_runners_on_contacted_at_and_id ON ci_runners USING btree (contacted_at, id);
+
+CREATE INDEX index_ci_runners_on_created_at_and_id ON ci_runners USING btree (created_at, id);
 
 CREATE INDEX index_ci_runners_on_description_trigram ON ci_runners USING gin (description gin_trgm_ops);