Abstract: In processing a transaction, a data storage system of a processing system stores and updates a progression created for the transaction that represents a timeline of events that occurred related to the transaction. When an event for a transaction occurs, the data storage system identifies data associated with the event. The data storage system creates an event signature for the event by hashing together the identified data. The data storage system identifies a stored progression of the transaction. The data storage system identifies a transaction signature included in the last record added to the progression. The data storage system creates a transaction signature for the event based on the transaction signature of the last record and the event signature created for the event. The data storage system adds a new record to the progression for the event and includes the transaction signature created for the event in the new record.