konfliktserialiserbar

Konfliktserialiserbar is a term used in database systems and concurrent programming to describe a property of schedules. A schedule is a sequence of operations performed by multiple transactions. A schedule is considered konfliktserialiserbar if its outcome is equivalent to some serial execution of the same transactions. Serial execution means that each transaction is completed entirely before the next one begins, thus avoiding any interleaving of operations.

The equivalence to a serial schedule implies that the concurrent execution, despite its interleaving, achieves the same final state of the database as if the transactions had run one after another. This is crucial for maintaining data integrity and consistency in systems where multiple users or processes access shared data simultaneously.

The concept of conflict serialisability is a practical way to ensure correctness for concurrent transactions. A conflict arises when two operations from different transactions access the same data item, and at least one of them is a write operation. If two operations conflict, their relative order in a concurrent schedule matters. A schedule is konfliktserialiserbar if, for every pair of conflicting operations, their relative order in the concurrent schedule is the same as their relative order in at least one possible serial schedule.

Testing for konfliktserialisability typically involves constructing a precedence graph. This graph represents the order of operations. If the graph contains no cycles, the schedule is konfliktserialiserbar. This property is a fundamental concept in understanding and implementing concurrency control mechanisms in database management systems.