Program Transformations for Asynchronous and Batched Query Submission

Abstract

Abstract-The performance of database/Web-service backed applications can be significantly improved by asynchronous submission of queries/requests well ahead of the point where the results are needed, so that results are likely to have been fetched already when they are actually needed. However, manually writing applications to exploit asynchronous query submission is tedious and error-prone. In this paper we address the issue of automatically transforming a program written assuming synchronous query submission, to one that exploits asynchronous query submission. Our program transformation method is based on data flow analysis and is framed as a set of transformation rules. Our rules can handle query executions within loops, unlike some of the earlier work in this area. We also present a novel approach that, at runtime, can combine multiple asynchronous requests into batches, thereby achieving the benefits of batching in addition to that of asynchronous submission. We have built a tool that implements our transformation techniques on Java programs that use JDBC calls; our tool can be extended to handle Web service calls. We have carried out a detailed experimental study on several real-life applications, which shows the effectiveness of the proposed rewrite techniques, both in terms of their applicability and the performance gains achieved.

Understanding Database Performance Inefficiencies in Real-world Web Applications

“…However, it only mentioned two anti-patterns from three Hibernate-based applications. We believe such anti-patterns are addressed by previous work [21,29]. We instead provide a thorough study of nine patterns of queryrelated performance problems on a larger range of applications, and discuss solutions that were not covered in prior work.…”

Turbocharging database query processing and testing

“…This performance robustness of Spill-Bound is quantified in Figa to speed up data access. The transformations successfully carry out batching and asynchronous submission of queries, 6 prefetching of query results, and conversion of procedural code to SQL. A metaphorical depiction of batching rewrites in DBridge is shown in Figure 2, where queries that are issued one-at-a-time, symbolized by the individual "taxis," are batched into a single unified request, carried by a "bus."…”

Cobra: A Framework for Cost-Based Rewriting of Database Applications

“…Note that unlike earlier techniques in DBridge [13], [3], [4], the focus of this paper is not on the program transformations themselves; rather we focus on representing various alternatives produced by one or more transformations of imperative code and choosing the least cost alternative. Our implementation of COBRA uses DBridge as a sub-system for generating alternative programs by applying these transformations.…”