Let's Play Tag: Linear Time Evaluation of Conjunctive Queries under TGD Constraints

Fuente: arXiv
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Main Authors: Carmeli, Nofar, Lutz, Carsten, Przybyłko, Marcin
Format: Preprint
Published: 2026
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author Carmeli, Nofar
Lutz, Carsten
Przybyłko, Marcin
author_facet Carmeli, Nofar
Lutz, Carsten
Przybyłko, Marcin
contents We study the limits of linear time evaluation of conjunctive queries under constraints expressed as tuple-generating dependencies (TGDs), across several modes of query evaluation: single-testing, all-testing, counting, lexicographic direct access, and enumeration. While full classifications seem far beyond reach, we propose an approach that, for some evaluation modes and classes of TGDs, makes it possible to lift known dichotomies from the unconstrained setting. In particular, our approach applies to all mentioned evaluation modes except enumeration, when the constraints fall into one of two classes: non-recursive sets of TGDs in which every TGD uses at most binary relation symbols in the head or has at most two frontier variables; and frontier-guarded full TGDs. We further provide a collection of examples showcasing the challenges that arise for enumeration and for less restrictive classes of TGDs.
format Preprint
id arxiv_https___arxiv_org_abs_2603_18709
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Let's Play Tag: Linear Time Evaluation of Conjunctive Queries under TGD Constraints
Carmeli, Nofar
Lutz, Carsten
Przybyłko, Marcin
Databases
We study the limits of linear time evaluation of conjunctive queries under constraints expressed as tuple-generating dependencies (TGDs), across several modes of query evaluation: single-testing, all-testing, counting, lexicographic direct access, and enumeration. While full classifications seem far beyond reach, we propose an approach that, for some evaluation modes and classes of TGDs, makes it possible to lift known dichotomies from the unconstrained setting. In particular, our approach applies to all mentioned evaluation modes except enumeration, when the constraints fall into one of two classes: non-recursive sets of TGDs in which every TGD uses at most binary relation symbols in the head or has at most two frontier variables; and frontier-guarded full TGDs. We further provide a collection of examples showcasing the challenges that arise for enumeration and for less restrictive classes of TGDs.
title Let's Play Tag: Linear Time Evaluation of Conjunctive Queries under TGD Constraints
topic Databases
url https://arxiv.org/abs/2603.18709