1. A method for upgrading a database that is still being accessed in an online service, comprising: starting an upgrade process of a database used in the online service that includes updating a schema that is used by the database; wherein the database being upgraded continues to receive, and process, and perform requests from web servers for database operations throughout the upgrade process of the schema; upgrading the schema of the database currently being utilized to an upgraded schema; wherein the upgraded schema is backwards compatible with the schema; after upgrading the schema to the upgraded schema, upgrading web servers of the online service to use the upgraded schema; and the upgraded web servers accessing the database using the upgraded schema.