Durability (computer science)
Encyclopedia
In database system
s, durability is the ACID
property which guarantees that transaction
s that have committed will survive permanently.
For example, if a flight booking reports that a seat has successfully been booked, then the seat will remain booked even if the system crashes.
Durability can be achieved by flushing the transaction's log records to non-volatile storage before acknowledging commitment.
In distributed transaction
s, all participating servers must coordinate before commit can be acknowledged. This is usually done by a two-phase commit protocol.
Many DBMSs implement durability by writing transactions into a transaction log that can be reprocessed to recreate the system state right before any later failure. A transaction is deemed committed only after it is entered in the log.
Database system
A database system is a term that is typically used to encapsulate the constructs of a data model, database Management system and database....
s, durability is the ACID
ACID
In computer science, ACID is a set of properties that guarantee database transactions are processed reliably. In the context of databases, a single logical operation on the data is called a transaction...
property which guarantees that transaction
Database transaction
A transaction comprises a unit of work performed within a database management system against a database, and treated in a coherent and reliable way independent of other transactions...
s that have committed will survive permanently.
For example, if a flight booking reports that a seat has successfully been booked, then the seat will remain booked even if the system crashes.
Durability can be achieved by flushing the transaction's log records to non-volatile storage before acknowledging commitment.
In distributed transaction
Distributed transaction
A distributed transaction is an operations bundle, in which two or more network hosts are involved. Usually, hosts provide transactional resources, while the transaction manager is responsible for creating and managing a global transaction that encompasses all operations against such resources...
s, all participating servers must coordinate before commit can be acknowledged. This is usually done by a two-phase commit protocol.
Many DBMSs implement durability by writing transactions into a transaction log that can be reprocessed to recreate the system state right before any later failure. A transaction is deemed committed only after it is entered in the log.
See also
- Atomicity
- Consistency
- IsolationIsolation (computer science)In database systems, isolation is a property that defines how/when the changes made by one operation become visible to other concurrent operations. Isolation is one of the ACID properties.-Isolation levels:...
- Relational database management systemRelational database management systemA relational database management system is a database management system that is based on the relational model as introduced by E. F. Codd. Most popular databases currently in use are based on the relational database model....