When running OLTP workloads on flash SSDs, relational DBMSs still face the write durability overhead, severely limiting their performance. To address this challenge, we propose NV-PPL, a novel database architecture that leverages NVDIMM as a durable log cache. NV-PPL captures per-page redo logs and retains them on NVDIMM to absorb writes from DRAM to SSD. Our NV-PPL prototype, deployed on an actual NVDIMM device, demonstrates superior transaction throughput, surpassing the same-priced Vanilla MySQL by at least 6.9× and NV-SQL, a page-grained NVDIMM caching scheme, by up to 1.5×. Beyond write reduction, the page-wise logs in NVDIMM enable novel approaches such as redo-less recovery and redo-based multi-versioning. Compared to Vanilla MySQL, redo-less recovery reduces recovery time by one-third, while redo-based multi-versioning enhances the latency of long-lived transactions in HTAP workloads by 3× to 18×.
By leveraging NV-DIMM as a durable log cache, we are able to surpass the same-priced Vanilla OLTP (On-Line Transaction Processing) system by up to an order of magnitude in terms of transaction throughput and reduce the recovery time by one-third.
Bohyun Lee, Seongjae Moon, Jonghyeok Park, Sang-Won Lee
Proceedings of the ACM on Management of Data 3 (1), 1-28
