| 摘要: |
| B＋树在数据库系统中已成为一种标准的索引结构，其上的并发控制机制对多用户数据库系统的性能有很大的影响．本文提出了一种变种B＋树──弹性B＋树－ｅ—B＋树（ｅｌａｓｔｉｃＢ＋－ｔｒｅｅ），定义了其上的安全点和操作及并发控制方法，对ｅ—B＋树的重构时机也进行了调整，降低了ｅ—B＋树上结点的合并／分裂频率，减少了ｅ—B＋树的维护开销，也缩短了封锁时间，从而使得其上操作的并发度和系统的效率得以提高． |
| 关键词: 并发度 合并 分裂 安全点 封锁 |
| DOI： |
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| e-B＋ -TREE:AN INDEXING ORGANIZATION OPTIMIZED FOR DBMS SUPPORTING MULTI-USERS |
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Gong Yuchang,Wang Weihong
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| Abstract: |
| B＋ -trees are considered standard organization for indexes in database systems. The concurrent control mechanism on B＋ -trees has a great effect on the performance of DBMS supporting multi-users. A variant of B＋ -tree called e-B＋ -tree(elastic B＋ -tree) is presented in this paper. Then, the safe nodes and operations on e--B＋ trees are defined and the moment of reconstruction of e-B＋tree is regulated. All these measures not only reduce the overhead for maintaining the e--B＋ tree and the time spent on locking, but also decrease the frequency of splitting and catenating operation. Therefore, the degree of concurrency of operations on e-B＋tree and efficiency of the database system can increase by a big margin. |
| Key words: Degree of concurrecy catenat split safe node lock. |
