[Research] [Research] A research paper of Professor Lee Sang-won's lab (Lee Bo-hyun's master's course) is approved by the VLDB 2023
- College of Software and Engineering
- Hit1038
- 2023-05-04
VLDB Laboratory (Advisory Professor: Lee Sang-won) Master's Program, Dr. Ahn Mi-jin (graduated) "LRU-C: Parallelizing Database I/Os for Flash SSDs" has been approved for publication in the 49th International Conference on Very Large Data Bases (VLDB). The VLDB is a top-tier academic conference in the field of databases and is held in Vancouver, Canada.
[Research contents]
Traditional database buffer managers serialize I/O requests due to readstall and mutex conflicts. Serialized I/O reduces storage and CPU utilization, limiting transaction throughput and latency. This damage is noticeable in flash SSDs with asymmetric read-write speeds and rich I/O parallelism.
In this work, we propose a novel approach to database buffering, LRU-C method, to leverage parallelization of flash SSDs by requesting database I/O in parallel. Introduces an LRU-C pointer to the most recently deprecated clean page in the LRU list. If you miss the page, LRU-C selects the current LRU clean page as vitim and adjusts the pointer to the next LRU Clean page on the LRU list. In this way, LRU-C can prevent I/O serialization due to readstall. The LRU-C pointer proposes two optimizations: dynamic batch write and parallel LRU list management to improve I/O throughput. The former can flush more dirty pages at once, while the latter mitigates I/O serialization caused by two mutex. Running OLTP workloads using the MySQL-based LRU-C prototype on flash SSDs resulted in a 3x and 1.5x improvement in transaction throughput and a significant reduction in tail latency over Vanilla MySQL and state-of-the-art WAR solutions, respectively. LRU-C reduces the hit ratio slightly, but increases I/O throughput, which significantly offsets the drop in the hit ratio.