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Does query evaluation tractability help query containment?

Pablo Barceló, Miguel Romero, Moshe Y. Vardi
2014 Proceedings of the 33rd ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems - PODS '14  
We study such question in detail and show that the situation is much more delicate than expected: First, tractability of UCQs does not help in general, but further restricting Θ to be acyclic and have  ...  This motivated us to study the question of whether restricting Θ to belong to a tractable class also helps alleviate the complexity of checking whether Π is contained in Θ.  ...  Tractability results for query evaluation and containment extend to these classes [31] .  ... 
doi:10.1145/2594538.2594553 dblp:conf/pods/Barcelo0V14 fatcat:tpomtn2llbdztgkbvei7dwlh6a

Conjunctive-Query Containment and Constraint Satisfaction

Phokion G. Kolaitis, Moshe Y. Vardi
2000 Journal of computer and system sciences (Print)  
Conjunctive-query containment is recognized as a fundamental problem in database query evaluation and optimization.  ...  This can be applied to conjunctive-query containment via Booleanization; in particular, it yields one of the known tractable cases of conjunctive-query containment.  ...  In particular, Georg Gottlob helped us clarify the relationship between treewidth and incidence treewidth in Section 5. We are also grateful to the referees for their useful comments.  ... 
doi:10.1006/jcss.2000.1713 fatcat:nsudggoadveq7ltautnewjybju

Conjunctive-query containment and constraint satisfaction

Phokion G. Kolaitis, Moshe Y. Vardi
1998 Proceedings of the seventeenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems - PODS '98  
Conjunctive-query containment is recognized as a fundamental problem in database query evaluation and optimization.  ...  This can be applied to conjunctive-query containment via Booleanization; in particular, it yields one of the known tractable cases of conjunctive query containment.  ...  In particular, Georg Gottlob helped us clarify the relationship between treewidth and incidence treewidth in Section 5.  ... 
doi:10.1145/275487.275511 dblp:conf/pods/KolaitisV98 fatcat:7ymts42phjd35nqqfdaqcpckpm

Containment join size estimation

Wei Wang, Haifeng Jiang, Hongjun Lu, Jeffrey Xu Yu
2003 Proceedings of the 2003 ACM SIGMOD international conference on on Management of data - SIGMOD '03  
In this paper, we report our study on one of the challenges in XML query optimization: containment join size estimation.  ...  Containment join is well accepted as an important operation in XML query processing. Estimating the size of its results is no doubt essential to generate efficient XML query processing plans.  ...  Accurate estimation of the intermediate result sizes, in this example, can help to choose a better query execution plan.  ... 
doi:10.1145/872773.872777 fatcat:hsyvwlcszvbcvouqlwahurx4di

Containment join size estimation

Wei Wang, Haifeng Jiang, Hongjun Lu, Jeffrey Xu Yu
2003 Proceedings of the 2003 ACM SIGMOD international conference on on Management of data - SIGMOD '03  
In this paper, we report our study on one of the challenges in XML query optimization: containment join size estimation.  ...  Containment join is well accepted as an important operation in XML query processing. Estimating the size of its results is no doubt essential to generate efficient XML query processing plans.  ...  Accurate estimation of the intermediate result sizes, in this example, can help to choose a better query execution plan.  ... 
doi:10.1145/872757.872777 dblp:conf/sigmod/WangJLY03 fatcat:3fxbjvtfcvdjborsuqahypknmm

The impact of virtual views on containment

Michael Benedikt, Georg Gottlob
2010 Proceedings of the VLDB Endowment  
However the use of iterative view definitions makes very simple query evaluation and analysis problems more complex.  ...  In this paper we study classical containment and equivalence problems for queries built up through simple unions of conjunctive queries and view definitions.  ...  The previous results show that restricting the right-hand side does not help matters.  ... 
doi:10.14778/1920841.1920882 fatcat:jdqggput5nalfa2czgnh36nfu4

Improved Cardinality Estimation by Learning Queries Containment Rates [article]

Rojeh Hayek, Oded Shmueli
2019 arXiv   pre-print
We describe a novel approach for estimating queries result-cardinalities using estimated containment rates among queries.  ...  We directly estimate containment rates between pairs of queries over a specific database.  ...  On the one hand, the generated QP contains "similar" queries to query Q, these can help the machine in predicting the cardinality.  ... 
arXiv:1908.07723v1 fatcat:nstbd4jbcvg57m27sekd25nvpi

Containment of queries for graphs with data

Egor V. Kostylev, Juan L. Reutter, Domagoj Vrgoč
2018 Journal of computer and system sciences (Print)  
We also propose extensions of regular queries with an inverse operator, and study query evaluation and query containment for them.  ...  In this paper we consider the containment problem for several recently proposed classes of queries that manipulate both topology and data: regular queries with memory, regular queries with data tests,  ...  The data complexity of RQDs' evaluation is the same as for RQMs-in NLogSpace, but the combined complexity is much better, in fact tractable, in PTime [32].  ... 
doi:10.1016/j.jcss.2017.09.005 fatcat:xg5repbc6nd2xkq3awj75x3c6q

Query Containment for Highly Expressive Datalog Fragments [article]

Pierre Bourhis and Markus Krötzsch and Sebastian Rudolph
2014 arXiv   pre-print
The containment problem of Datalog queries is well known to be undecidable.  ...  We generalize MQs to (Frontier-)Guarded Queries (GQs), and show that the containment problem is 3ExpTime-complete in either case, even if we allow arbitrary Datalog in the sub-query.  ...  Most notably, Datalog has been widely studied as a very expressive query language with tractable query answering (w.r.t. the size of the database).  ... 
arXiv:1406.7801v1 fatcat:cn5rocfztfg5rhey4kgsexu5o4

Chasing One's Tail: XPath Containment Under Cyclic DTDs

Manizheh Montazerian, Peter T. Wood
2011 International Workshop/Symposium on Database Programming Languages  
The problem of finding subclasses of XPath queries and document type definitions (DTDs) for which containment can be tested efficiently has been much studied.  ...  so allows us to produce a complete procedure for containment using the chase and previous classes of constraints.  ...  ACKNOWLEDGEMENTS We would like to thank the anonymous reviewers for their constructive comments which helped to improve the paper.  ... 
dblp:conf/dbpl/MontazerianW11 fatcat:podxexsnabg6he4hb5nzkr3l4e

Containment units

Jamieson M. Cobleigh, Leon J. Osterweil, Alexander Wise, Barbara Staudt Lerner
2002 Proceedings of the tenth ACM SIGSOFT symposium on Foundations of software engineering - SIGSOFT '02/FSE 10  
We present examples of Containment Units used within robotics along with the results of actual executions, and the application of static analysis to obtain assurances that those Containment Units can be  ...  We present Containment Units as a software architecture useful for recognizing environmental changes and dynamically reconfiguring software and resource allocations to adapt to those changes.  ...  discussions on the analysis of Containment Units, and Rodion Podorozhny, Anoop George Ninan, and Joel Sieh for developing the resource manager.  ... 
doi:10.1145/587051.587076 dblp:conf/sigsoft/CobleighOWL02 fatcat:puhnckfslzcz7lfaldjhe7eueu

Containment of acyclic conjunctive queries with negated atoms or arithmetic comparisons

Evgeny Sherkhonov, Maarten Marx
2017 Information Processing Letters  
Since then there have been a number of papers on generalizing the acyclicity condition while keeping the evaluation and containment problems tractable.  ...  There has been little work on finding fragments of CQs with negated atoms or comparisons that have tractable query containment.  ... 
doi:10.1016/j.ipl.2016.12.005 fatcat:5gttsywndbevpi5lv6yut2xvpq

Containment and Optimization of Object-Preserving Conjunctive Queries

Edward P. F. Chan, Ron van der Meyden
2000 SIAM journal on computing (Print)  
We rst characterize the containment and minimization conditions for the class of terminal conjunctive queries.  ...  We then characterize containment for the class of all conjunctive queries, and derive an optimization algorithm for this class.  ...  However, determining if a terminal conjunctive query is satis able is tractable.  ... 
doi:10.1137/s0097539794262446 fatcat:2frzprzozjfyvko3iffzrdawim

Monadic Datalog, Tree Validity, and Limited Access Containment

Michael Benedikt, Pierre Bourhis, Georg Gottlob, Pierre Senellart
2019 ACM Transactions on Computational Logic  
We reconsider the problem of containment of monadic datalog (MDL) queries in unions of conjunctive queries (UCQs).  ...  We then present a general approach for getting tighter bounds on the complexity of query containment, based on analysis of the number of mappings of queries into tree-like instances.  ...  IQ-Types and Containment of MDL in UCQs How does the machinery of the last subsection help us?  ... 
doi:10.1145/3344514 fatcat:pei6ekjgybasdmz37o4wlrxeku

Query Containment of Tier-2 Queries over a Probabilistic Database

Katherine F. Moore, Vibhor Rastogi, Christopher Ré, Dan Suciu
2009 International VLDB workshop on Management of Uncertain Data  
We would like to thank Hyunjung Park for several helpful discussions. Acknowledgements This work was partially funded by NSF IIS-0713576 and the eScience Institute at the University of Washington.  ...  Additionally, their result states that when the queries are restricted to propositional logic the construction is in NP. However, this work does not consider query containment.  ...  , but practically important, classes of probabilistic databases, such as tuple independent probabilistic databases, and (3) we plan to find tractable subclasses of queries for the containment problem.  ... 
dblp:conf/mud/MooreRRS09 fatcat:k25665bptbcafkpbvke5a7egta
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