Txbegin

Txbegin is a term used in software development to denote the initiation of a transaction in various transactional systems. A transaction is a sequence of operations that are intended to be completed as a single unit of work, such that either all operations succeed or none do. The function or directive named txbegin typically signals the start of this unit and is followed by a corresponding commit or abort.

Contexts: In relational databases, the common literal is BEGIN or BEGIN TRANSACTION, but some libraries and APIs expose a function or macro named txbegin to start a transaction programmatically. In transactional memory, txbegin marks the beginning of a transaction that encompasses reads and writes to shared memory. In distributed or multi-resource transactions, txbegin may coordinate with a transaction manager to ensure atomicity across databases, message queues, and other resources.

Semantics: Beginning a transaction often establishes an isolation context, records the set of read and write operations, and defers durable persistence until commit. If the operations succeed, a txcommit finalizes changes; if an error or conflict occurs, txabort or rollback undoes changes. Nested transactions and savepoints, if supported, allow partial rollbacks.

Variants and compatibility: The exact syntax, behavior, and support for features such as nested transactions, savepoints, and recovery vary by system. Therefore txbegin is not a universal standard keyword; it appears in specific APIs, libraries, or language bindings rather than as a general SQL keyword.