Undecidable optimization problems for database logic programs

Gaifman, Haim; Mairson, Harry G.; Sagiv, Yehoshua; Vardi, Moshe Y.

doi:10.1145/174130.174142

Cited by 75 publications

(60 citation statements)

References 11 publications

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“…Previous work on datalog on arbitrary structures often considered the case of connected programs [11,13]. A practical reason is that "real life" programs tend to be connected and linear (cf.…”

Section: Datalog and Rtpqsmentioning

confidence: 99%

“…Classical static analysis problems of containment and equivalence are undecidable [18]. It is also undecidable if a given datalog program is equivalent to some non-recursive datalog program [13] (equivalence to a given non-recursive program is decidable [10]). Since these problems are subtasks in important data management tasks like query minimization, data integration, or data exchange, the negative results for full datalog fuel interest in restrictions [5,7,8].…”

Section: Introductionmentioning

confidence: 99%

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Monadic Datalog and Regular Tree Pattern Queries

Mazowiecki

Murlak

Witkowski

2016

ACM Trans. Database Syst.

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Abstract. Containment of monadic datalog programs over trees is decidable. The situation is more complex when tree nodes carry labels from an infinite alphabet that can be tested for equality. Then, it matters whether descendant relation is allowed or not: descendant relation can be eliminated easily from monadic programs only when label equalities are not used. With descendant, even containment of linear monadic programs in unions of conjunctive queries is undecidable and positive results are known only for bounded-depth trees. We show that without descendant containment of connected monadic programs is decidable over ranked trees, but over unranked trees it is decidable only for linear programs. With descendant it becomes decidable over unranked trees under restriction to downward programs: in each rule we only go down from the node in the head. This restriction is motivated by the formalism of regular tree pattern queries, recently proposed in the area of ActiveXML, which we show to be equivalent to linear downward programs.

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Section: Datalog and Rtpqsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Monadic Datalog and Regular Tree Pattern Queries

Mazowiecki

Murlak

Witkowski

2016

ACM Trans. Database Syst.

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“…Using the construction presented by Gaifman et al [19], it is possible to write a Datalog program that encodes any two-counter machine's transition relation and an arbitrarily long finite successor relation in the EDB, and define a 0-ary output relation accept that is true if and only if the two-counter machine accepts and the transition and successor relations are valid. As the construction is possible in Datalog, it is also possible in Dedalus.…”

Section: Appendixmentioning

confidence: 99%

Confluence Analysis for Distributed Programs: A Model-Theoretic Approach

Marczak

Alvaro

Conway

et al. 2012

Lecture Notes in Computer Science

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Building on recent interest in distributed logic programming, we take a model-theoretic approach to analyzing confluence of asynchronous distributed programs. We begin with a model-theoretic semantics for Dedalus and develop the concept of ultimate models to capture the non-deterministic eventual outcomes of distributed programs. After demonstrating the undecidability of checking confluence for Dedalus programs, we look for restricted sub-languages that guarantee confluence while providing adequate expressivity. We observe that a simple semipositive restriction called Dedalus + guarantees confluence while capturing PTIME, but demonstrate that the limited use of negation in Dedalus + makes certain simple and practical programs very difficult to express. To remedy this, we introduce Dedalus S , a restriction of Dedalus that allows a natural use of negation in the spirit of stratified negation, but retains the confluence of Dedalus + and similarly captures PTIME.

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“…In [9], it was shown that undecidability of boundedness can be translated into undecidability for many other properties. The translation, however, is not applicable to our context because none of the IB notions is semantic.…”

Section: U T 6 Decision Problems For Increment Boundednessmentioning

confidence: 99%

Increment boundedness and nonrecursive incremental evaluation of datalog queries

Dong

1995

Database Theory — ICDT '95

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Abstract. Given a recursive (datalog) query, the nonrecursive incremental evaluation approach uses nonrecursive (datalog) programs to compute the difference of the answers to the query against successive databases between updates. The mechanism used in this approach is called a "First-Order Incremental Evaluation System" (FOIES). We show that for two large classes of datalog queries, called "generalized (weakly) regular queries", FOIES always exist. We also define "increment boundedness" and its variations, which generalize boundedness. Increment bounded queries are shown to have FOIES of certain forms. We also relate increment boundedness to structural recursion, which was proposed for bulk data types. We characterize increment boundednessusing the "insertion idempotency", "insertion commutativity", and "determinism" properties of structural recursion. Finally, we show that the increment boundedness notions are undecidable and a decidable sufficient condition is given.

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Undecidable optimization problems for database logic programs

Cited by 75 publications

References 11 publications

Monadic Datalog and Regular Tree Pattern Queries

Monadic Datalog and Regular Tree Pattern Queries

Confluence Analysis for Distributed Programs: A Model-Theoretic Approach

Increment boundedness and nonrecursive incremental evaluation of datalog queries

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