two-phase commit


Also found in: Dictionary, Thesaurus, Medical, Legal, Financial.

two-phase commit

(database)
A technique for maintaining integrity in distributed databases. Where a system uses two or more database, a transaction among the distibuted database should be atomic ("all or nothing"). This is done by handling the transaction in two phases. First the databases prepare the transaction, confirm that it is possible to process it, and lock the relevant record.

Once all the required databases confirm that the transaction is viable, the system instructs them all to commit it - i.e. to make it permanent. If it is not possible to process it, the system will instruct the databases to rollback (undo) the transaction.

two-phase commit

A technique for ensuring that a transaction successfully updates all appropriate files in a distributed database environment. All DBMSs involved in the transaction first confirm that the transaction has been received and is recoverable (stored on disk). Then each DBMS is told to commit the transaction (do the actual updating).

Traditionally, two-phase-commit meant updating databases in two or more servers, but the term is also applied to updating two or more different databases within the same server. See transaction, transaction file and transaction processing.
References in periodicals archive ?
By partnering with NEON Systems, we are able to deliver a solution that provides Swiss Mobiliar Insurance Company with consistent information throughout their enterprise utilizing NEON Systems' two-phase commit technology," said Joe Menard, president of the BEA E-Commerce Server Division.
In general, two-phase commit protocols are blocking, whereas the three-phase commit protocol is nonblocking.
A key element of the solution, which needs to support hundreds of transactions per second, was complete support of two-phase commit.
eXtremeDB's two-phase commit protocol facilitates instantaneous fail-over, with zero replication-induced latency.
Arjuna's transaction service adds fully distributed transactional support using two-phase commit coordination to JBoss, thereby allowing distributed transactions to span application server instances and multiple heterogeneous data sources.
McObject's eXtremeDB High Availability solves these limitations through an innovative architecture, based on a rugged, time-cognizant two-phase commit protocol that ensures changes to the main instance (MI) database and identical standby instances (SI) succeed or fail together.
This includes knowledge of Structured Query Language (SQL Access standard) for primary interface that extends the interface to access databases over a network; decision support (DSS) features; related transaction processing systems, which include concurrency control, figure isolation, dynamic load balancing, configuration management, message queue management, two-phase commit and transactional RPC.
Distributed Transaction management and full two-phase commit for Oracle and ASE databases in any combination -- SMP support for Oracle data access -- Lightweight directory access protocol for Sybase Adaptive Server Enterprise and Oracle data access -- Large object binaries enabling retrieval and replication of extremely large portions of data in binary and character format on Oracle and Microsoft SQL Server -- Support column data and row data sizes up to the maximum allowed for each targeted database -- Support for Oracle Unicode datatypes -- Updated mainframe SNA connectivity support on the Sun platform, which now supports Sun's newer SNA add-on, SNAP-IX -- Support for DB2 UDB on NT and UNIX