US Patent 9990391 Transactional messages in journal-based storage systems

A journal manager of a multi-data-store storage system receives a transaction which includes a message to be stored in the storage system's journal if the transaction request is accepted for commit. The journal manager performs a conflict detection operation, accepts the transaction request, and stores a corresponding committed transaction entry including the message in the journal. A write applier associated with a registered materialization node of the journal reads the committed transaction entry and applies a write indicated in the entry. A registered message subscriber of the journal reads the committed transaction entry asynchronously with respect to the write applier, and reads the contents of the message without applying the write.