Extend index on ci_builds_metadata

Relates to https://gitlab.com/gitlab-org/gitlab/-/issues/296755

changelogs/unreleased/ab-ci-builds-metadata-index.yml

+---
+title: Extend index on ci_builds_metadata
+merge_request: 52123
+author:
+type: performance

db/migrate/20210120180956_extend_index_on_ci_builds_metadata.rb

+# frozen_string_literal: true
+
+class ExtendIndexOnCiBuildsMetadata < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  OLD_INDEX = :index_ci_builds_metadata_on_build_id_and_interruptible
+  NEW_INDEX = :index_ci_builds_metadata_on_build_id_and_id_and_interruptible
+
+  TABLE = :ci_builds_metadata
+
+  def up
+    create_covering_index(TABLE, NEW_INDEX)
+
+    remove_concurrent_index_by_name TABLE, OLD_INDEX
+  end
+
+  def down
+    add_concurrent_index TABLE, :build_id, where: 'interruptible = true', name: OLD_INDEX
+
+    remove_concurrent_index_by_name TABLE, NEW_INDEX
+  end
+
+  private
+
+  def create_covering_index(table, name)
+    return if index_exists_by_name?(table, name)
+
+    disable_statement_timeout do
+      execute <<~SQL
+        CREATE INDEX CONCURRENTLY #{name}
+        ON #{table} (build_id) INCLUDE (id)
+        WHERE interruptible = true
+      SQL
+    end
+  end
+end

db/schema_migrations/20210120180956

+897815c347f04093da5eba420e95b6310454bd493412914e60a296bd710ebde1
\ No newline at end of file

db/structure.sql

@@ -21622,7 +21622,7 @@ CREATE UNIQUE INDEX index_ci_builds_metadata_on_build_id ON ci_builds_metadata U
 
 CREATE INDEX index_ci_builds_metadata_on_build_id_and_has_exposed_artifacts ON ci_builds_metadata USING btree (build_id) WHERE (has_exposed_artifacts IS TRUE);
 
-CREATE INDEX index_ci_builds_metadata_on_build_id_and_interruptible ON ci_builds_metadata USING btree (build_id) WHERE (interruptible = true);
+CREATE INDEX index_ci_builds_metadata_on_build_id_and_id_and_interruptible ON ci_builds_metadata USING btree (build_id) INCLUDE (id) WHERE (interruptible = true);
 
 CREATE INDEX index_ci_builds_metadata_on_project_id ON ci_builds_metadata USING btree (project_id);