Techniques for processing events are provided. In one embodiment, a plurality of records is received. The plurality of records is generated by one or more computer systems and represents a plurality of events that have occurred in these computer systems. The plurality of events is processed, where processing the plurality of events comprises storing the plurality of records in an append-only sequence. The append-only sequence is a storage representation of the plurality of events that allows only appending new records that represent new events but does not allow modifying and deleting existing records that represent already existing events. One or more expressions are then evaluated based on the plurality of records that are stored in the append-only sequence.