In order to efficiently handle change notification requests to a storage system based on a database data store and a database engine, the change notification requests are multiplexed. This can be done by issuing a query which refers, for information about what changes are being tracked, to a data structure. The information about what changes to track for each request to be multiplexed is stored in the data structure. Additionally, information about the request can be stored in the data structure. By adding information to the data structure, the query can be altered without needing to directly modify or reissue the query.