Multi-Version Databases on Flash: Append Storage and Access Paths

Abstract—New storage technologies, such as Flash and Non-Volatile Memories, with fundamentally different properties are appearing. Leveraging their performance and endurance requires a redesign of existing architecture and algorithms in modern high performance databases. Multi-Version Concurrency Control (MVCC) approaches in database systems, maintain multiple timestamped versions of a tuple. Once a transaction reads a tuple the database system tracks and returns the respective version eliminating lock-requests. Hence, under MVCC reads are never blocked, which leverages well the excellent read performance (high throughput, low latency) of new storage technologies. The read performance is also utilised by the read-intensive visibility and validity rules (MVCC, Snapshot Isolation) that filter the latest committed version of a tuple that a transaction can see out of the set of all tuple versions. Much more critical is the updat