307An Overview of the NoSQL World
throughput The disadvantage is the greater risk of data loss if a server
crashes and loses unsynched updates.
• Synchronous vs. asynchronous replication: Synchronous replication
ensures all copies are up-to-date but potentially incurs high latency on
updates. Furthermore, availability may be impacted if synchronously
replicated updates cannot complete while some replicas are ofine.
Asynchronous replication avoids high write latency but allows replicas to
be stale. Furthermore, data loss may occur if an update is lost due to failure
before it can be replicated.
• Data partitioning: Systems may be strictly row-based or allow for column
storage. Row-based storage supports efcient access to an entire record a ...