Abstract: Emerging non-volatile memory(NVM) is taking people’s attention.Due to the advantages of low latency,persistence,large capacity and byte-addressable,database system can run on the NVM-only storage architecture.In this configuration,some novel logless indexing structures come into being and are expected to recover indexing capability immediately after an system failure.However,under the current computer architecture,these structures need a large amount of synchronizations to ensure data consistency,which leads to a severe performance penalty.NVM-baesd logless hash table leverages the atomic update of the pointer data to ensure the consistency.An optimized rehash procedure was proposed to not only reduce the synchronizations during normal execution,but also ensure the instant recovery after system failures.Performance evaluation shows that,compared with existing persistent indexing structures,logless hash tables perform well under most workloads,and have significant advantages in terms of recovery time,NVM footprint,and write wear.

Key words: Indexing structure, Instantly recoverable, Non-volatile memory, Persistence