Atomicitat

Atomicitat, or atomicity, is the quality of being atomic: indivisible and irreducible from the standpoint of a system. In computing, an operation or a sequence of operations is atomic if it appears to the rest of the system as a single, indivisible step: either it completes entirely or has no effect at all. This property helps prevent partially applied updates and inconsistent states in concurrent environments.

In database theory, atomicity is one of the ACID properties that govern reliable transactions. A transaction is atomic if its attempted changes are committed as a unit or rolled back entirely if any part fails, leaving the database in a consistent state. Recovery mechanisms, logging, and commit/rollback protocols enforce this guarantee.

In programming and hardware, atomic operations are those that cannot be interrupted. Languages and libraries provide atomic primitives (such as atomic variables or synchronization instructions) to implement lock-free data structures and safe concurrent updates. An operation is atomic if it is indivisible at the memory model level; readers will not observe intermediate states.

Across distributed systems, achieving global atomicity is challenging; practical approaches include two-phase commit, distributed transactions, or design patterns favoring idempotent or compensating operations rather than true cross-node atomicity. The concept is related to, but distinct from, isolation and durability in the broader ACID framework.

Etymology: the term derives from Latin atomus, meaning indivisible; in many languages it is rendered as atomicitat or atomicidad.