two-phase commit

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.

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(database)

two-phase commit - 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.