In this work, we propose B 3 -tree , a hybrid index for persistent memory that leverages the byte-addressability of the in-memory index and the page locality of B-trees. As in the byte-addressable in-memory index, B 3 -tree is updated by 8-byte store instructions. Also, as in disk-based index, B 3 -tree is failure-atomic since it makes every 8-byte store instruction transform a consistent index into another consistent index without the help of expensive logging. Since expensive logging becomes unnecessary, the number of cacheline flush instructions required for B 3 -tree is significantly reduced. Our performance study shows that B 3 -tree outperforms other state-of-the-art persistent indexes in terms of insert and delete performance. While B 3 -tree shows slightly worse performance for point query performance, the range query performance of B 3 -tree is 2x faster than FAST and FAIR B-tree because the leaf page size of B 3 -tree can be set to 8x larger than that of FAST and FAIR B-tree without degrading insertion performance. We also show that read transactions can access B 3 -tree without acquiring a shared lock because B 3 -tree remains always consistent while a sequence of 8-byte write operations are making changes to it. As a result, B 3 -tree provides high concurrency level comparable to FAST and FAIR B-tree.

中文翻译：

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B 3 - 树

在这项工作中，我们建议乙3-树，一种用于持久内存的混合索引，它利用内存索引的字节寻址能力和 B 树的页面局部性。与字节可寻址的内存索引一样，乙3-树由 8 字节存储指令更新。此外，与基于磁盘的索引一样，乙3-树是失败原子的，因为它使每个 8 字节的存储指令都将一个一致的索引转换为另一个一致的索引，而无需昂贵的日志记录的帮助。由于不需要昂贵的日志记录，因此需要的高速缓存行刷新指令的数量乙3-树显着降低。我们的绩效研究表明乙3-树在插入和删除性能方面优于其他最先进的持久索引。尽管乙3-树点查询性能稍差，范围查询性能为乙3-树比 FAST 和 FAIR B-tree 快 2 倍，因为叶页大小为乙3-树可以设置为比 FAST 和 FAIR B-tree 大 8 倍，而不会降低插入性能。我们还展示了读取事务可以访问乙3-树没有获取共享锁，因为乙3-树当一系列 8 字节写操作对其进行更改时，它始终保持一致。因此，乙3-树提供与 FAST 和 FAIR B-tree 相当的高并发级别。