59,391 research outputs found
Enhancing Predicate Pairing with Abstraction for Relational Verification
Relational verification is a technique that aims at proving properties that
relate two different program fragments, or two different program runs. It has
been shown that constrained Horn clauses (CHCs) can effectively be used for
relational verification by applying a CHC transformation, called predicate
pairing, which allows the CHC solver to infer relations among arguments of
different predicates. In this paper we study how the effects of the predicate
pairing transformation can be enhanced by using various abstract domains based
on linear arithmetic (i.e., the domain of convex polyhedra and some of its
subdomains) during the transformation. After presenting an algorithm for
predicate pairing with abstraction, we report on the experiments we have
performed on over a hundred relational verification problems by using various
abstract domains. The experiments have been performed by using the VeriMAP
transformation and verification system, together with the Parma Polyhedra
Library (PPL) and the Z3 solver for CHCs.Comment: Pre-proceedings paper presented at the 27th International Symposium
on Logic-Based Program Synthesis and Transformation (LOPSTR 2017), Namur,
Belgium, 10-12 October 2017 (arXiv:1708.07854
Deductive Optimization of Relational Data Storage
Optimizing the physical data storage and retrieval of data are two key
database management problems. In this paper, we propose a language that can
express a wide range of physical database layouts, going well beyond the row-
and column-based methods that are widely used in database management systems.
We use deductive synthesis to turn a high-level relational representation of a
database query into a highly optimized low-level implementation which operates
on a specialized layout of the dataset. We build a compiler for this language
and conduct experiments using a popular database benchmark, which shows that
the performance of these specialized queries is competitive with a
state-of-the-art in memory compiled database system
Relational Constraint Driven Test Case Synthesis for Web Applications
This paper proposes a relational constraint driven technique that synthesizes
test cases automatically for web applications. Using a static analysis,
servlets can be modeled as relational transducers, which manipulate backend
databases. We present a synthesis algorithm that generates a sequence of HTTP
requests for simulating a user session. The algorithm relies on backward
symbolic image computation for reaching a certain database state, given a code
coverage objective. With a slight adaptation, the technique can be used for
discovering workflow attacks on web applications.Comment: In Proceedings TAV-WEB 2010, arXiv:1009.330
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