DBSpinner: Making a Case for Iterative Processing in Databases
DBSpinner: Making a Case for Iterative Processing in Databases
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DOI：
10.1109/icde51399.2021.00273
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发表时间：
2021-04
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影响因子：
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通讯作者：
Sofoklis Floratos;A. Ghazal;Jason Sun;Jianjun Chen;Xiaodong Zhang
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作者：
Sofoklis Floratos;A. Ghazal;Jason Sun;Jianjun Chen;Xiaodong Zhang
关系数据库管理系统（RDBMS）的迭代处理支持有限，但是，递归查询已添加到ANSI SQL中，但是，它们的语义不允许聚集功能，这使其在几种应用程序中的使用，例如Pagerank和最短的路径计算提出了SQL扩展，迭代公共表表达式（CTE），以使用户能够在RDBMS上执行一般迭代计算。在此工作1中，我们证明了如何有效地将CTE纳入生产RDBM，而无需大量侵入系统。现有的SQL运算符还针对迭代CTES应用了几种优化，以最大程度地减少数据移动，ii）保持恒定的重复使用结果，iii）按下谓词以避免不必要的数据处理。结果表明，重写方法的可行性以及优化的有效性，在某些情况下，可以提高性能。
Relational database management systems (RDBMS) have limited iterative processing support. Recursive queries were added to ANSI SQL, however, their semantics do not allow aggregation functions, which disqualifies their use for several applications, such as PageRank and shortest path computations. Recently, another SQL extension, iterative Common Table Expressions (CTEs), is proposed to enable users to perform general iterative computations on RDBMSs.In this work1, we demonstrate how iterative CTEs can be efficiently incorporated into a production RDBMS without major intrusion to the system. We have prototyped our approach on Futurewei’s MPPDB, a shared nothing relational parallel database engine. The implementation is based on a functional rewrite that translates iterative CTEs to other existing SQL operators. Thus, query plans of iterative CTEs can be optimized and executed by the engine with minimal modification to the code base. We have also applied several optimizations specifically for iterative CTEs to i) minimize data movement, ii) reuse results that remain constant and iii) push down predicates to avoid unnecessary data processing. We verified our implementation through extensive experimental evaluation using real world datasets and queries. The results show the feasibility of the rewrite approach and the effectiveness of the optimizations, which improve performance by an order of magnitude in some cases.