Abstract: A method for preventing a loss of memory data is provided. The method includes: when a first stream pattern matching engine starts pattern matching, creating a state machine in a memory of the first stream pattern matching engine; in a pattern matching process, obtaining, by the first stream pattern matching engine, an event from an event storage apparatus in sequence according to a pattern matching rule; and snapshotting a state of the state machine according to a snapshot rule, to form a snapshot file, and saving the snapshot file in a snapshot storage apparatus, where the snapshot file records an offset of the obtained event in the event storage apparatus. Reliability of memory data is improved by using the method.

Abstract: The present invention relates to data synchronization and discloses a method and a system for data synchronization and a relevant device. The method includes: in a process of database-level synchronization between a first database and a second database, sending a request for creating a transaction to the first database; when the first database executes the transaction, acquiring a sequence number from the first database, and sending the operation command required for executing the transaction and the sequence number corresponding to the transaction to a temporary storage queue for storage; acquiring a switching sequence number from the second database when a database-level synchronization link between the first database and the second database is disconnected; determining a sequence number that is stored in the temporary storage queue and follows the switching sequence number, and sending the operation command required to the second database.