Fine-grained replication and scheduling with freshness and correctness guarantees
Fuat Akal, Can Türker, Hans‐Jörg Schek, Yuri J. Breitbart, Torsten Grabs, Lourens E. Veen · 2005
Lazy replication protocols provide good scalabil-ity properties by decoupling transaction execution from the propagation of new values to replica sites while guaranteeing a correct and more efficient transaction processing and replica maintenance. However, they impose several restrictions that are often not valid in practical database settings, e.g., they require that each transaction executes at its initiation site and/or are restricted to full replica-tion schemes. Also, the protocols cannot guaran-tee that the transactions will always see the fresh-est available replicas. This paper presents a new lazy replication protocol called PDBREP that is free of these restrictions while ensuring one-copy-serializable executions. The protocol exploits the distinction between read-only and update transac-tions and works with arbitrary physical data orga-nizations such as partitioning and striping as well as different replica granularities. It does not re-quire that each read-only transaction executes en-tirely at its initiation site. Hence, each read-only site need not contain a fully replicated database. PDBREP moreover generalizes the notion of fresh-ness to finer data granules than entire databases. 1