Opportunities for optimism in contended main-memory multicore transactions
Opportunities for optimism in contended main-memory multicore transactions
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DOI：
10.1007/s00778-021-00719-9
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发表时间：
2020-01
期刊：
影响因子：
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通讯作者：
Yihe Huang;William Qian;E. Kohler;B. Liskov;L. Shrira
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文献类型：
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作者：
Yihe Huang;William Qian;E. Kohler;B. Liskov;L. Shrira
主存多核事务系统使用单版本乐观并发控制（OCC）实现了出色的性能，特别是在无竞争的工作负载上。尽管如此，基于其他并发控制协议的系统，如混合OCC/锁定和多版本并发控制（MVCC）的变化，据报道优于最好的OCC系统，特别是随着竞争的增加。本文表明，实现选择无关的并发控制可以解释这些性能差异。我们的评估显示了OCC，MVCC和TicToc并发控制在不同的工作负载和竞争水平下的优势和劣势，以及几个实施选择的重要性，称为基础因素。考虑到合理的基本因子选择，OCC性能不会在高争用TPC-C上崩溃。我们还提出了两种优化技术，延迟更新和时间戳分裂，可以显着提高OCC和MVCC的高竞争性能。这些技术都是已知的，但我们将它们应用到一个新的环境中，并强调它们的潜力：当它们结合在一起时，它们可以在TPC-C工作负载中为MVCC和OCC带来性能提升。
Main-memory multicore transactional systems have achieved excellent performance using single-version optimistic concurrency control (OCC), especially on uncontended workloads. Nevertheless, systems based on other concurrency control protocols, such as hybrid OCC/ locking and variations on multiversion concurrency control (MVCC), are reported to outperform the best OCC systems, especially with increasing contention. This paper shows that implementation choices unrelated to concurrency control can explain some of these performance differences. Our evaluation shows the strengths and weaknesses of OCC, MVCC, and TicToc concurrency control under varying workloads and contention levels, and the importance of several implementation choices calledbasis factors. Given sensible basis factor choices, OCC performance does not collapse on high-contention TPC-C. We also present two optimization techniques,deferred updatesandtimestamp splitting, that can dramatically improve the high-contention performance of both OCC and MVCC. These techniques are known, but we apply them in a new context and highlight their potency: when combined, they lead to performance gains offor MVCC andfor OCC in a TPC-C workload.