Protocol (database)

Protocols are synchronization methods that are used by transaction systems to make the parallel execution of transactions efficient. Usually a separate component of the transaction system, the so-called scheduler , implements the corresponding protocol.

Examples are locking protocols such as the two-phase locking protocol ( 2-phase lock , abbreviation 2PL ) or the various tree lock procedures ( tree lock , abbreviation TL ), as well as time stamp- based protocols ( time ordering , abbreviation TO ) and serializability -graph protocols ( Serializability graph scheduling , abbr. SGT ). For the execution of transactions in distributed systems will commit protocols used. The subsystems involved agree on whether a transaction can be completed successfully or whether it must be canceled.