publications: - title: "Dependable cardinality forecasts for XQuery" author: - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" - name: "Torsten Grust" link: "http://www-db.informatik.uni-tuebingen.de/team/grust" - name: "Sebastian Maneth" link: "http://www.cse.unsw.edu.au/~smaneth/" - name: "Sherif Sakr" link: "https://researchr.org/alias/sherif-sakr" year: "2008" doi: "http://www.vldb.org/pvldb/1/1453908.pdf" abstract: "Though inevitable for effective cost-based query rewriting, the derivation of meaningful cardinality estimates has remained a notoriously hard problem in the context of XQuery. By basing the estimation on a relational representation of the XQuery syntax, we show how existing cardinality estimation techniques for XPath and proven relational estimation machinery can play together to yield dependable forecasts for arbitrary XQuery (sub)expressions. Our approach benefits from a light-weight form of data flow analysis. Abstract domain identifiers guide our query analyzer through the estimation process and allow for informed decisions even in case of deeply nested XQuery expressions. A variant of projection paths provides a versatile interface into which existing techniques for XPath cardinality estimation can be plugged in seamlessly. We demonstrate an implementation of this interface based on data guides. Experiments show how our approach can equally cope with both, structure- and value-based queries. It is robust with respect to intermediate estimation errors, from which we typically found our implementation to recover gracefully." links: doi: "http://www.vldb.org/pvldb/1/1453908.pdf" tags: - "Cost Estimation" - "relational data base" - "rule-based" - "intermediate representation" - "XQuery" - "abstract syntax" - "graph query" - "XPath" - "domain analysis" - "analysis" - "data-flow" - "graph-rewriting" - "context-aware" - "rewriting" - "data-flow analysis" - "systematic-approach" researchr: "https://researchr.org/publication/TeubnerGMS08" cites: 20 citedby: 2 journal: "PVLDB" volume: "1" number: "1" pages: "463-477" kind: "article" key: "TeubnerGMS08" - title: "Snowfall: Hardware Stream Analysis Made Easy" author: - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" - name: "Louis Woods" link: "http://www.systems.ethz.ch/people/lwoods" year: "2011" abstract: "Field-programmable gate arrays (FPGAs) are chip devices that can be runtime-reconfigured to realize arbitrary processing tasks directly in hardware. Industrial products as well as research prototypes demonstrated how this capability can be exploited to build highly efficient processors for data warehousing, data mining, or stream analysis tasks. On the flip side, the construction of dedicated hardware circuits requires considerable engineering efforts and skills that are often not available in application-focussed development teams. To bridge this gap, at ETH we have developed a set of tools that aid developers of high-performance stream processing solutions and enable agile hardware generation for changing application demands. In this demonstration, we showcase Snowfall, a compiler tool for low-level stream analysis. Comparable to scanner generators for software-based systems (e.g., lex/flex), Snowfall can be used to decode incoming data streams in hardware, react to low-level patterns in a stream, and perform initial input data analysis. Snowfall plays well together with Glacier, a query-to-hardware compiler that we described and demonstrated in. A typical use case is to use Snowfall for input parsing and pre-processing, then perform SQL-style query processing on top with a hardware query plan obtained with the help of Glacier. In the demo, we illustrate Snowfall based on a real-world use case with exceptionally high demands for throughput and latency. With the help of Snowfall, we perform risk checking for financial trading applications. Snowfall allows for a declarative description of the problem, yet will generate a hardware circuit that can process input streams in real time. " links: dblp: "http://dblp.uni-trier.de/rec/bibtex/conf/btw/TeubnerW09" tags: - "FPGA" - "rule-based" - "program analysis" - "SQL" - "analysis" - "data-flow programming" - "data-flow" - "software engineering" - "compiler" - "data-flow analysis" - "parsing" - "stream processing" researchr: "https://researchr.org/publication/TeubnerW09" cites: 0 citedby: 0 pages: "738-741" booktitle: "Datenbanksysteme für Business, Technologie und Web (BTW), 14. Fachtagung des GI-Fachbereichs Datenbanken und Informationssysteme (DBIS), 2.-4.3.2011 in Kaiserslautern, Germany" editor: - name: "Theo Härder" link: "https://researchr.org/alias/theo-h%26auml%3Brder" - name: "Wolfgang Lehner" link: "https://researchr.org/alias/wolfgang-lehner" - name: "Bernhard Mitschang" link: "https://researchr.org/alias/bernhard-mitschang" - name: "Harald Schöning" link: "https://researchr.org/alias/harald-sch%26ouml%3Bning" - name: "Holger Schwarz" link: "https://researchr.org/alias/holger-schwarz" volume: "180" series: "LNI" publisher: "GI" isbn: "978-3-88579-274-1" kind: "inproceedings" key: "TeubnerW09" - title: "A Spinning Join That Does Not Get Dizzy" author: - name: "Philip Werner Frey" link: "https://researchr.org/profile/philipwernerfrey/publications" - name: "Romulo Goncalves" link: "https://researchr.org/profile/romulogoncalves/publications" - name: "Martin L. Kersten" link: "http://homepages.cwi.nl/~mk/" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2010" doi: "http://doi.ieeecomputersociety.org/10.1109/ICDCS.2010.23" abstract: "As network infrastructures with 10 Gb/s bandwidth and beyond have become pervasive and as cost advantages of large commodity-machine clusters continue to increase, research and industry strive to exploit the available processing performance for large-scale database processing tasks. In this work we look at the use of high-speed networks for distributed join processing. We propose Data Roundabout as a lightweight transport layer that uses Remote Direct Memory Access (RDMA) to gain access to the throughput opportunities in modern networks. The essence of Data Roundabout is a ring-shaped network in which each host stores one portion of a large database instance. We leverage the available bandwidth to (continuously) pump data through the high-speed network. Based on Data Roundabout, we demonstrate cyclo-join, which exploits the cycling flow of data to execute distributed joins. The study uses different join algorithms (hash join and sort-merge join) to expose the pitfalls and the advantages of each algorithm in the data cycling arena. The experiments show the potential of a large distributed main-memory cache glued together with RDMA into a novel distributed database architecture. " links: doi: "http://doi.ieeecomputersociety.org/10.1109/ICDCS.2010.23" dblp: "http://dblp.uni-trier.de/rec/bibtex/conf/icdcs/FreyGKT10" tags: - "cyclo-join" - "high-speed network" - "rule-based" - "caching" - "architecture" - "data-flow" - "database" - "distributed database" - "RDMA" researchr: "https://researchr.org/publication/FreyGKT10" cites: 25 citedby: 1 pages: "283-292" booktitle: "2010 International Conference on Distributed Computing Systems, ICDCS 2010, Genova, Italy, June 21-25, 2010" publisher: "IEEE Computer Society" isbn: "978-0-7695-4059-7" kind: "inproceedings" key: "FreyGKT10" - title: "MonetDB/XQuery-Consistent and Efficient Updates on the Pre/Post Plane" author: - name: "Peter A. Boncz" link: "http://homepages.cwi.nl/~boncz/" - name: "Jan Flokstra" link: "http://wwwhome.cs.utwente.nl/~flokstra/" - name: "Torsten Grust" link: "http://www-db.informatik.uni-tuebingen.de/team/grust" - name: "Maurice van Keulen" link: "http://www.vf.utwente.nl/~keulen/" - name: "Stefan Manegold" link: "http://homepages.cwi.nl/~manegold/" - name: "K. Sjoerd Mullender" link: "http://homepages.cwi.nl/~sjoerd/" - name: "Jan Rittinger" link: "http://www-db.informatik.uni-tuebingen.de/team/rittinger" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2006" doi: "http://dx.doi.org/10.1007/11687238_89" abstract: "Relational XQuery processors aim at leveraging mature relational DBMS query processing technology to provide scalability and efficiency. To achieve this goal, various storage schemes have been proposed to encode the tree structure of XML documents in flat relational tables. Basically, two classes can be identified: (1) encodings using fixed-length surrogates, like the preorder ranks in the pre/post encoding [5] or the equivalent pre/size/level encoding [8], and (2) encodings using variable-length surrogates, like, e.g., ORDPATH [9] or P-PBiTree [12]. Recent research [1] showed a clear advantage of the former for efficient evaluation of XPath location steps, exploiting techniques like cheap node order tests, positional lookup, and node skipping in staircase join [7]. However, once updates are involved, variable-length surrogates are often considered the better choice, mainly as a straightforward implementation of structural XML updates using fixed-length surrogates faces two performance bottlenecks: (i) high physical cost (the preorder ranks of all nodes following the update position must be modified—on average 50% of the document), and (ii) low transaction concurrency (updating the size of all ancestor nodes causes lock contention on the document root). In [4], we presented techniques that allow an efficient and ACID-compliant implementation of XML updates also on the pre/post (respectively pre/size/level encoding) without sacrificing its superior XPath (i.e., read-only) performance. This demonstration describes in detail, how we successfully implemented these techniques in MonetDB/XQuery [2, 1], an XML database system with full-fledged XQuery support. The system consists of the Pathfinder compiler that translates and optimizes XQuery into relational algebra [6], on top of the high-performance MonetDB relational database engine [3]." links: doi: "http://dx.doi.org/10.1007/11687238_89" tags: - "optimization" - "XQuery" - "translation" - "relational database" - "XML" - "XML Schema" - "process algebra" - "XPath" - "testing" - "relational algebra" - "compiler" - " algebra" - "database" researchr: "https://researchr.org/publication/BonczFGKMMRT06" cites: 0 citedby: 0 pages: "1190-1193" booktitle: "Advances in Database Technology - EDBT 2006, 10th International Conference on Extending Database Technology, Munich, Germany, March 26-31, 2006, Proceedings" editor: - name: "Yannis E. Ioannidis" link: "https://researchr.org/alias/yannis-e.-ioannidis" - name: "Marc H. Scholl" link: "https://researchr.org/alias/marc-h.-scholl" - name: "Joachim W. Schmidt" link: "https://researchr.org/alias/joachim-w.-schmidt" - name: "Florian Matthes" link: "https://researchr.org/alias/florian-matthes" - name: "Michael Hatzopoulos" link: "https://researchr.org/alias/michael-hatzopoulos" - name: "Klemens Böhm" link: "https://researchr.org/alias/klemens-b%C3%B6hm" - name: "Alfons Kemper" link: "https://researchr.org/alias/alfons-kemper" - name: "Torsten Grust" link: "http://www-db.informatik.uni-tuebingen.de/team/grust" - name: "Christian Böhm" link: "https://researchr.org/alias/christian-b%C3%B6hm" volume: "3896" series: "Lecture Notes in Computer Science" publisher: "Springer" isbn: "3-540-32960-9" kind: "inproceedings" key: "BonczFGKMMRT06" - title: "The ETH Zurich systems group and enterprise computing center" author: - name: "Gustavo Alonso" link: "http://www.systems.ethz.ch/people/alonso" - name: "Donald Kossmann" link: "http://www.systems.ethz.ch/people/donaldk" - name: "Timothy Roscoe" link: "http://www.inf.ethz.ch/personal/troscoe/" - name: "Nesime Tatbul" link: "http://www.inf.ethz.ch/personal/tatbul/" - name: "Andrew Baumann" link: "http://www.systems.ethz.ch/people/andrewb" - name: "Carsten Binnig" link: "https://researchr.org/alias/carsten-binnig" - name: "Peter M. Fischer" link: "http://websci.informatik.uni-freiburg.de/people/fischer" - name: "Oriana Riva" link: "http://people.inf.ethz.ch/oriva/" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2008" doi: "http://doi.acm.org/10.1145/1519103.1519120" links: doi: "http://doi.acm.org/10.1145/1519103.1519120" researchr: "https://researchr.org/publication/AlonsoKRTBBFRT08" cites: 0 citedby: 0 journal: "SIGMOD Record" volume: "37" number: "4" pages: "94-99" kind: "article" key: "AlonsoKRTBBFRT08" - title: "Accelerating XPath evaluation in any RDBMS" author: - name: "Torsten Grust" link: "http://www-db.informatik.uni-tuebingen.de/team/grust" - name: "Maurice van Keulen" link: "http://www.vf.utwente.nl/~keulen/" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2004" doi: "http://doi.acm.org/10.1145/974750.974754" abstract: "This article is a proposal for a database index structure, the XPath accelerator, that has been specifically designed to support the evaluation of XPath path expressions. As such, the index is capable to support all XPath axes (including ancestor, following, preceding-sibling, descendant-or-self, etc.). This feature lets the index stand out among related work on XML indexing structures which had a focus on the child and descendant axes only. The index has been designed with a close eye on the XPath semantics as well as the desire to engineer its internals so that it can be supported well by existing relational database query processing technology: the index (a) permits set-oriented (or, rather, sequence-oriented) path evaluation, and (b) can be implemented and queried using well-established relational index structures, notably B-trees and R-trees.We discuss the implementation of the XPath accelerator on top of different database backends and show that the index performs well on all levels of the memory hierarchy, including disk-based and main-memory based database systems." links: doi: "http://doi.acm.org/10.1145/974750.974754" tags: - "semantics" - "rule-based" - "relational database" - "XML" - "XML Schema" - "XPath" - "database" researchr: "https://researchr.org/publication/GrustKT04" cites: 0 citedby: 2 journal: "ACM Trans. Database Syst." volume: "29" pages: "91-131" kind: "article" key: "GrustKT04" - title: "Data Processing on FPGAs" author: - name: "René Müller" link: "http://www.systems.ethz.ch/people/muellren" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" - name: "Gustavo Alonso" link: "http://www.systems.ethz.ch/people/alonso" year: "2009" doi: "http://www.vldb.org/pvldb/2/vldb09-603.pdf" abstract: "Computer architectures are quickly changing toward heterogeneous many-core systems. Such a trend opens up interesting opportunities but also raises immense challenges since the efficient use of heterogeneous many-core systems is not a trivial problem. In this paper, we explore how to program data processing operators on top of field-programmable gate arrays (FPGAs). FPGAs are very versatile in terms of how they can be used and can also be added as additional processing units in standard CPU sockets. In the paper, we study how data processing can be accelerated using an FPGA. Our results indicate that efficient usage of FPGAs involves non-trivial aspects such as having the right computation model (an asynchronous sorting network in this case); a careful implementation that balances all the design constraints in an FPGA; and the proper integration strategy to link the FPGA to the rest of the system. Once these issues are properly addressed, our experiments show that FPGAs exhibit performance figures competitive with those of modern general-purpose CPUs while offering significant advantages in terms of power consumption and parallel stream evaluation." links: doi: "http://www.vldb.org/pvldb/2/vldb09-603.pdf" tags: - "power consumption" - "FPGA" - "meta programming" - "sorting networks" - "case study" - "meta-model" - "architecture" - "parallel programming" - "constraints" - "data-flow programming" - "data-flow" - "source-to-source" - "Meta-Environment" - "design" - "process modeling" - "open-source" - "stream processing" researchr: "https://researchr.org/publication/MuellerTA09" cites: 29 citedby: 4 journal: "PVLDB" volume: "2" number: "1" pages: "910-921" kind: "article" key: "MuellerTA09" - title: "Pathfinder: XQuery - The Relational Way" author: - name: "Peter A. Boncz" link: "http://homepages.cwi.nl/~boncz/" - name: "Torsten Grust" link: "http://www-db.informatik.uni-tuebingen.de/team/grust" - name: "Maurice van Keulen" link: "http://www.vf.utwente.nl/~keulen/" - name: "Stefan Manegold" link: "http://homepages.cwi.nl/~manegold/" - name: "Jan Rittinger" link: "http://www-db.informatik.uni-tuebingen.de/team/rittinger" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2005" doi: "http://www.vldb.org/conf/2005/papers/p1322-boncz.pdf" abstract: "Relational query processors are probably the best understood (as well as the best engineered) query engines available today. Although carefully tuned to process instances of the relational model (tables of tuples), these processors can also provide a foundation for the evaluation of “alien” (non-relational) query languages: if a relational encoding of the alien data model and its associated query language is given, the RDBMS may act like a special-purpose processor for the new language. This demonstration features our XQuery compiler Pathfinder, the continuation of our earlier work on a purely relational XPath and XQuery processing stack in which we developed relational encodings and processing strategies for the tree-shaped XML data model. The Pathfinder project is an exploration of how far we can push the idea of using mature RDBMS technology to design and build a full-fledged XQuery implementation. The demonstration will show that this line of research was and still is worth to be followed: based on the extensible relational database kernel MonetDB, Pathfinder provides highly efficient and scalable XQuery technology that scales beyond 10 GB XML input instances on commodity hardware. Pathfinder requires only local extensions to the underlying DBMS’s kernel, such as the staircase join operator. A join recognition logic in our compiler, as well as a careful consideration of order properties of relational operators, allow for effective optimizations that turn MonetDB into a highly efficient XQuery engine." links: doi: "http://www.vldb.org/conf/2005/papers/p1322-boncz.pdf" tags: - "optimization" - "relational data base" - "rule-based" - "XQuery" - "data-flow language" - "relational database" - "meta-model" - "XML" - "modeling language" - "XML Schema" - "language modeling" - "design research" - "XPath" - "language design" - "data-flow" - "compiler" - "database" - "logic" - "Meta-Environment" - "design" - "process modeling" - "extensible language" - "query language" researchr: "https://researchr.org/publication/BonczGKMRT05" cites: 10 citedby: 1 pages: "1322-1325" booktitle: "Proceedings of the 31st International Conference on Very Large Data Bases, Trondheim, Norway, August 30 - September 2, 2005" editor: - name: "Klemens Böhm" link: "https://researchr.org/alias/klemens-b%C3%B6hm" - name: "Christian S. Jensen" link: "https://researchr.org/alias/christian-s.-jensen" - name: "Laura M. Haas" link: "https://researchr.org/alias/laura-m.-haas" - name: "Martin L. Kersten" link: "https://researchr.org/alias/martin-l.-kersten" - name: "Per-Åke Larson" link: "https://researchr.org/alias/per-%C3%A5ke-larson" - name: "Beng Chin Ooi" link: "https://researchr.org/alias/beng-chin-ooi" publisher: "ACM" isbn: "1-59593-154-6" kind: "inproceedings" key: "BonczGKMRT05" - title: "XQuery on SQL Hosts" author: - name: "Torsten Grust" link: "http://www-db.informatik.uni-tuebingen.de/team/grust" - name: "Sherif Sakr" link: "http://www.cse.unsw.edu.au/~ssakr/" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2004" doi: "http://www.vldb.org/conf/2004/RS7P1.PDF" abstract: "Relational database systems may be turned into efficient XML and XPath processors if the system is provided with a suitable relational tree encoding. This paper extends this relational XML processing stack and shows that an RDBMS can also serve as a highly efficient XQuery runtime environment. Our approach is purely relational: XQuery expressions are compiled into SQL code which operates on the tree encoding. The core of the compilation procedure trades XQuery's notions of variable scopes and nested iteration (FLWOR blocks) for equi-joins. The resulting relational XQuery processor closely adheres to the language semantics, e.g., it respects node identity as well as document and sequence order, and can support XQuery's full axis feature. The system exhibits quite promising performance figures in experiments. Somewhat unexpectedly, we will also see that the XQuery compiler can make good use of SQL's OLAP functionality." links: doi: "http://www.vldb.org/conf/2004/RS7P1.PDF" tags: - "semantics" - "XQuery" - "Loop Lifting" - "operating system" - "relational database" - "XML" - "XML Schema" - "SQL" - "XPath" - "compiler" - "database" - "Meta-Environment" - "systematic-approach" researchr: "https://researchr.org/publication/GrustST04" cites: 0 citedby: 10 pages: "252-263" booktitle: "(e)Proceedings of the Thirtieth International Conference on Very Large Data Bases, Toronto, Canada, August 31 - September 3 2004" editor: - name: "Mario A. Nascimento" link: "https://researchr.org/alias/mario-a.-nascimento" - name: "M. Tamer Özsu" link: "https://researchr.org/alias/m.-tamer-%C3%B6zsu" - name: "Donald Kossmann" link: "https://researchr.org/alias/donald-kossmann" - name: "Renée J. Miller" link: "https://researchr.org/alias/ren%C3%A9e-j.-miller" - name: "José A. Blakeley" link: "https://researchr.org/alias/jos%C3%A9-a.-blakeley" - name: "K. Bernhard Schiefer" link: "https://researchr.org/alias/k.-bernhard-schiefer" publisher: "Morgan Kaufmann" isbn: "0-12-088469-0" kind: "inproceedings" key: "GrustST04" - title: "Pathfinder: XQuery Off the Relational Shelf" author: - name: "Torsten Grust" link: "http://www-db.informatik.uni-tuebingen.de/team/grust" - name: "Jan Rittinger" link: "http://www-db.informatik.uni-tuebingen.de/team/rittinger" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2008" doi: "http://sites.computer.org/debull/A08dec/pathfinder.pdf" abstract: "The Pathfinder project makes inventive use of relational database technology―originally developed to process data of strictly tabular shape―to construct efficient database-supported XML and XQuery processors. Pathfinder targets database engines that implement a set-oriented mode of query execution: many off-the-shelf traditional database systems make for suitable XQuery runtime environments, but a number of off-beat storage back-ends fit that bill as well. While Pathfinder has been developed with a close eye on the XQuery semantics, some of the techniques that we will review here will be generally useful to evaluate XQuery-style iterative languages on database back-ends. " links: doi: "http://sites.computer.org/debull/A08dec/pathfinder.pdf" tags: - "semantics" - "XQuery" - "relational XQuery" - "data-flow language" - "relational database" - "XML" - "XML Schema" - "data-flow" - "reviewing" - "database" - "Meta-Environment" - "query language" researchr: "https://researchr.org/publication/GrustRT08" cites: 26 citedby: 0 journal: "IEEE Data Eng. Bull." volume: "31" number: "4" pages: "7-14" kind: "article" key: "GrustRT08" - title: "Recursion in XQuery: put your distributivity safety belt on" author: - name: "Loredana Afanasiev" link: "https://researchr.org/alias/loredana-afanasiev" - name: "Torsten Grust" link: "http://www-db.informatik.uni-tuebingen.de/team/grust" - name: "Maarten Marx" link: "http://staff.science.uva.nl/~marx/" - name: "Jan Rittinger" link: "http://www-db.informatik.uni-tuebingen.de/team/rittinger" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2009" doi: "http://doi.acm.org/10.1145/1516360.1516401" abstract: "We introduce a controlled form of recursion in XQuery, an inflationary fixed point operator, familiar from the context of relational databases. This operator imposes restrictions on the expressible types of recursion, but it is sufficiently versatile to capture a wide range of interesting use cases, including Regular XPath and its core transitive closure operator. While the optimization of general user-defined recursive functions in XQuery appears elusive, we describe how inflationary fixed points can be efficiently evaluated, provided that the recursive XQuery expressions are distributive. We test distributivity syntactically and algebraically, and provide experimental evidence that XQuery processors can benefit substantially from this mode of evaluation." links: doi: "http://doi.acm.org/10.1145/1516360.1516401" tags: - "optimization" - "XQuery" - "relational database" - "Recursion" - "process algebra" - "XPath" - "testing" - "relational algebra" - " algebra" - "context-aware" - "Fixed Point" researchr: "https://researchr.org/publication/AfanasievGMRT09" cites: 29 citedby: 1 pages: "345-356" booktitle: "EDBT 2009, 12th International Conference on Extending Database Technology, Saint Petersburg, Russia, March 24-26, 2009, Proceedings" editor: - name: "Martin L. Kersten" link: "https://researchr.org/alias/martin-l.-kersten" - name: "Boris Novikov" link: "https://researchr.org/alias/boris-novikov" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" - name: "Vladimir Polutin" link: "https://researchr.org/alias/vladimir-polutin" - name: "Stefan Manegold" link: "http://homepages.cwi.nl/~manegold/" volume: "360" series: "ACM International Conference Proceeding Series" publisher: "ACM" isbn: "978-1-60558-422-5" kind: "inproceedings" key: "AfanasievGMRT09" - title: "Pathfinder: Compiling XQuery for Execution on the Monet Database Engine" author: - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2003" doi: "http://sunsite.informatik.rwth-aachen.de/Publications/CEUR-WS/Vol-76/teubner.pdf" links: doi: "http://sunsite.informatik.rwth-aachen.de/Publications/CEUR-WS/Vol-76/teubner.pdf" tags: - "XQuery" - "compiler" - "database" researchr: "https://researchr.org/publication/Teubner03" cites: 0 citedby: 0 booktitle: "Proceedings of the VLDB 2003 PhD Workshop. Co-located with the 29th International Conference on Very Large Data Bases (VLDB 2003). Berlin, September 12-13, 2003" editor: - name: "Marc H. Scholl" link: "https://researchr.org/alias/marc-h.-scholl" - name: "Torsten Grust" link: "http://www-db.informatik.uni-tuebingen.de/team/grust" volume: "76" series: "CEUR Workshop Proceedings" publisher: "CEUR-WS.org" kind: "inproceedings" key: "Teubner03" - title: "A SQL: 1999 code generator for the pathfinder xquery compiler" author: - name: "Torsten Grust" link: "http://www-db.informatik.uni-tuebingen.de/team/grust" - name: "Manuel Mayr" link: "http://www-db.informatik.uni-tuebingen.de/team/mayr" - name: "Jan Rittinger" link: "http://www-db.informatik.uni-tuebingen.de/team/rittinger" - name: "Sherif Sakr" link: "https://researchr.org/alias/sherif-sakr" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2007" doi: "http://doi.acm.org/10.1145/1247480.1247642" abstract: "The Pathfinder XQuery compiler has been enhanced by a new code generator that can target any SQL:1999-compliant relational database system (RDBMS). This code generator marks an important next step towards truly relational XQuery processing, a branch of database technology that aims to turn RDBMSs into highly efficient XML and XQuery processors without the need to invade the relational database kernel. Pathfinder, a retargetable front-end compiler, translates input XQuery expressions into DAG-shaped relational algebra plans. The code generator then turns these plans into sequences of either SQL:1999 statements or view definitions which jointly implement the (sometimes intricate) XQuery semantics. In a sense, this demonstration thus lets relational algebra and SQL swap their traditional roles in database query processing. The result is a code generator that (1) supports an almost complete dialect of XQuery, (2) can target any RDBMS with a SQL:1999 language interface, and (3) exhibits quite promising performance characteristics when run against high-volume XML data as well as complex XQuery expressions." links: doi: "http://doi.acm.org/10.1145/1247480.1247642" tags: - "semantics" - "XQuery" - "translation" - "completeness" - "data-flow language" - "relational database" - "XML" - "XML Schema" - "SQL" - "process algebra" - "relational algebra" - "data-flow" - "compiler" - " algebra" - "database" - "query language" researchr: "https://researchr.org/publication/GrustMRST07" cites: 8 citedby: 1 pages: "1162-1164" booktitle: "Proceedings of the ACM SIGMOD International Conference on Management of Data, Beijing, China, June 12-14, 2007" editor: - name: "Chee Yong Chan" link: "https://researchr.org/alias/chee-yong-chan" - name: "Beng Chin Ooi" link: "https://researchr.org/alias/beng-chin-ooi" - name: "Aoying Zhou" link: "https://researchr.org/alias/aoying-zhou" publisher: "ACM" isbn: "978-1-59593-686-8" kind: "inproceedings" key: "GrustMRST07" - title: "Spinning relations: high-speed networks for distributed join processing" author: - name: "Philip Werner Frey" link: "https://researchr.org/profile/philipwernerfrey/publications" - name: "Romulo Goncalves" link: "https://researchr.org/profile/romulogoncalves/publications" - name: "Martin L. Kersten" link: "http://homepages.cwi.nl/~mk/" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2009" doi: "http://doi.acm.org/10.1145/1565694.1565701" abstract: "By leveraging modern networking hardware (RDMA-enabled network cards), we can shift priorities in distributed database processing significantly. Complex and sophisticated mechanisms to avoid network traffic can be replaced by a scheme that takes advantage of the bandwidth and low latency offered by such interconnects. We illustrate this phenomenon with cyclo-join, an efficient join algorithm based on continuously pumping data through a ring-structured network. Our approach is capable of exploiting the resources of all CPUs and distributed main-memory available in the network for processing queries of arbitrary shape and datasets of arbitrary size." links: doi: "http://doi.acm.org/10.1145/1565694.1565701" tags: - "cyclo-join" - "rule-based" - "high-speed networks" - "data-flow" - "database" - "distributed database" - "systematic-approach" - "RDMA" researchr: "https://researchr.org/publication/FreyGKT09" cites: 15 citedby: 1 pages: "27-33" booktitle: "Proceedings of the Fifth International Workshop on Data Management on New Hardware, DaMoN 2009, Providence, Rhode Island, USA, June 28, 2009" editor: - name: "Peter A. Boncz" link: "https://researchr.org/alias/peter-a.-boncz" - name: "Kenneth A. Ross" link: "https://researchr.org/alias/kenneth-a.-ross" publisher: "ACM" isbn: "978-1-60558-701-1" kind: "inproceedings" key: "FreyGKT09" - title: "An Inflationary Fixed Point Operator in XQuery" author: - name: "Loredana Afanasiev" link: "https://researchr.org/alias/loredana-afanasiev" - name: "Torsten Grust" link: "http://www-db.informatik.uni-tuebingen.de/team/grust" - name: "Maarten Marx" link: "http://staff.science.uva.nl/~marx/" - name: "Jan Rittinger" link: "http://www-db.informatik.uni-tuebingen.de/team/rittinger" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2008" doi: "http://dx.doi.org/10.1109/ICDE.2008.4497604" abstract: "We introduce a controlled form of recursion in XQuery, an inflationary fixed point operator, familiar from the context of relational databases. This operator imposes restrictions on the expressible types of recursion, but we show that it is sufficiently versatile to capture a wide range of interesting use cases, including Regular XPath and its core transitive closure operator. While the optimization of general user-defined recursive functions in XQuery appears elusive, we describe how inflationary fixed points can be efficiently evaluated, provided that the recursive XQuery expressions are distributive. We test distributivity syntactically and algebraically, and provide experimental evidence that XQuery processors can benefit substantially from this mode of evaluation." links: doi: "http://dx.doi.org/10.1109/ICDE.2008.4497604" successor: "https://researchr.org/publication/AfanasievGMRT09" tags: - "optimization" - "XQuery" - "relational database" - "Recursion" - "process algebra" - "XPath" - "testing" - "relational algebra" - " algebra" - "context-aware" - "Fixed Point" researchr: "https://researchr.org/publication/AfanasievGMRT08" cites: 11 citedby: 1 pages: "1504-1506" booktitle: "Proceedings of the 24th International Conference on Data Engineering, ICDE 2008, April 7-12, 2008, Cancún, México" publisher: "IEEE" kind: "inproceedings" key: "AfanasievGMRT08" - title: "Pathfinder: A Relational Query Optimizer Explores XQuery Terrain" author: - name: "Jan Rittinger" link: "http://www-db.informatik.uni-tuebingen.de/team/rittinger" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" - name: "Torsten Grust" link: "http://www-db.informatik.uni-tuebingen.de/team/grust" year: "2007" doi: "http://www.btw2007.de/paper/p617.pdf" links: doi: "http://www.btw2007.de/paper/p617.pdf" tags: - "optimization" - "XQuery" researchr: "https://researchr.org/publication/RittingerTG07" cites: 7 citedby: 1 pages: "617-620" booktitle: "Datenbanksysteme in Business, Technologie und Web (BTW 2007), 12. Fachtagung des GI-Fachbereichs Datenbanken und Informationssysteme (DBIS), Proceedings, 7.-9. März 2007, Aachen, Germany" editor: - name: "Alfons Kemper" link: "https://researchr.org/alias/alfons-kemper" - name: "Harald Schöning" link: "https://researchr.org/alias/harald-sch%C3%B6ning" - name: "Thomas Rose" link: "https://researchr.org/alias/thomas-rose" - name: "Matthias Jarke" link: "https://researchr.org/alias/matthias-jarke" - name: "Thomas Seidl" link: "https://researchr.org/alias/thomas-seidl" - name: "Christoph Quix" link: "https://researchr.org/alias/christoph-quix" - name: "Christoph Brochhaus" link: "https://researchr.org/alias/christoph-brochhaus" volume: "103" series: "LNI" publisher: "GI" isbn: "978-3-88579-197-3" kind: "inproceedings" key: "RittingerTG07" - title: "FPGA acceleration for the frequent item problem" author: - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" - name: "René Müller" link: "http://www.systems.ethz.ch/people/muellren" - name: "Gustavo Alonso" link: "http://www.systems.ethz.ch/people/alonso" year: "2010" doi: "http://dx.doi.org/10.1109/ICDE.2010.5447856" abstract: "Field-programmable gate arrays (FPGAs) can provide performance advantages with a lower resource consumption (e.g., energy) than conventional CPUs. In this paper, we show how to employ FPGAs to provide an efficient and high-performance solution for the frequent item problem. We discuss three design alternatives, each one of them exploiting different FPGA features, and we provide an exhaustive evaluation of their performance characteristics. The first design is a one-to-one mapping of the Space-Saving algorithm (shown to be the best approach in software), built on special features of FPGAs: content-addressable memory and dual-ported BRAM. The two other implementations exploit the flexibility of digital circuits to implement parallel lookups and pipelining strategies, resulting in significant improvements in performance. On low-cost FPGA hardware, the fastest of our designs can process 80 million items per second—three times as much as the best known result. Moreover, and unlike in software approaches where performance is directly related to the skew factor of the Zipf distribution, the high throughput is independent of the skew of the distribution of the input. In the paper we discuss as well several design trade-offs that are relevant when implementing database functionality on FPGAs. In particular, we look at resource consumption and the levels of data and task parallelism of three different designs. " links: doi: "http://dx.doi.org/10.1109/ICDE.2010.5447856" dblp: "http://dblp.uni-trier.de/rec/bibtex/conf/icde/TeubnerMA10" tags: - "FPGA" - "frequent item" - "parallelism" - "functional programming" - "parallel programming" - "data mining" - "data-flow programming" - "data-flow" - "pipelining" - "database" - "design" - "systematic-approach" researchr: "https://researchr.org/publication/TeubnerMA10" cites: 16 citedby: 5 pages: "669-680" booktitle: "Proceedings of the 26th International Conference on Data Engineering, ICDE 2010, March 1-6, 2010, Long Beach, California, USA" editor: - name: "Feifei Li" link: "https://researchr.org/alias/feifei-li" - name: "Mirella M. Moro" link: "https://researchr.org/alias/mirella-m.-moro" - name: "Shahram Ghandeharizadeh" link: "https://researchr.org/alias/shahram-ghandeharizadeh" - name: "Jayant R. Haritsa" link: "https://researchr.org/alias/jayant-r.-haritsa" - name: "Gerhard Weikum" link: "https://researchr.org/alias/gerhard-weikum" - name: "Michael J. Carey" link: "https://researchr.org/alias/michael-j.-carey" - name: "Fabio Casati" link: "https://researchr.org/alias/fabio-casati" - name: "Edward Y. Chang" link: "https://researchr.org/alias/edward-y.-chang" - name: "Ioana Manolescu" link: "https://researchr.org/alias/ioana-manolescu" - name: "Sharad Mehrotra" link: "https://researchr.org/alias/sharad-mehrotra" - name: "Umeshwar Dayal" link: "https://researchr.org/alias/umeshwar-dayal" - name: "Vassilis J. Tsotras" link: "https://researchr.org/alias/vassilis-j.-tsotras" publisher: "IEEE" isbn: "978-1-4244-5444-0" kind: "inproceedings" key: "TeubnerMA10" - title: "The relational XQuery puzzle: a look-back on the pieces found so far" author: - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2009" doi: "http://dx.doi.org/10.1007/s00450-009-0058-8" abstract: "Given the tremendous versatility of relational database implementations toward a wide range of database problems, it seems only natural to consider them as back-ends for XML data processing. Yet, the assumptions behind the language XQuery are considerably different to those in traditional RDBMSs. The underlying data model is a tree, data and results carry an intrinsic order, queries are described using explicit iteration and, after all, problems are everything else but regular. Solving the relational XQuery puzzle, therefore, has challenged a number of research groups over the past years. The purpose of this article is to summarize and assess some of the results that have been obtained during this period to solve the puzzle. Our main focus is on the Pathfinder XQuery compiler, a full reference implementation of a purely relational XQuery processor. As we dissect its components, we relate them to other work in the field and also point to open problems and limitations in the context of relational XQuery processing." links: doi: "http://dx.doi.org/10.1007/s00450-009-0058-8" tags: - "XQuery" - "relational XQuery" - "data-flow language" - "relational database" - "meta-model" - "XML" - "modeling language" - "XML Schema" - "language modeling" - "XPath" - "relational XPath" - "data-flow" - "source-to-source" - "compiler" - "database" - "context-aware" - "Meta-Environment" - "process modeling" - "open-source" - "query language" researchr: "https://researchr.org/publication/Teubner09" cites: 49 citedby: 0 journal: "Inform., Forsch. Entwickl." volume: "24" number: "1-2" pages: "37-49" kind: "article" key: "Teubner09" - title: "Streams on Wires - A Query Compiler for FPGAs" author: - name: "René Müller" link: "http://www.systems.ethz.ch/people/muellren" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" - name: "Gustavo Alonso" link: "http://www.systems.ethz.ch/people/alonso" year: "2009" doi: "http://www.vldb.org/pvldb/2/vldb09-622.pdf" abstract: "Taking advantage of many-core, heterogeneous hardware for data processing tasks is a difficult problem. In this paper, we consider the use of FPGAs for data stream processing as co-processors in many-core architectures. We present Glacier, a component library and compositional compiler that transforms continuous queries into logic circuits by composing library components on an operator-level basis. In the paper we consider selection, aggregation, grouping, as well as windowing operators, and discuss their design as modular elements. We also show how significant performance improvements can be achieved by inserting the FPGA into the system's data path (e.g., between the network interface and the host CPU). Our experiments show that queries on the FPGA can process streams at more than one million tuples per second and that they can do this directly from the network, removing much of the overhead of transferring the data to a conventional CPU." links: doi: "http://www.vldb.org/pvldb/2/vldb09-622.pdf" tags: - "FPGA" - "architecture" - "composition" - "data-flow" - "compiler" - "logic" - "design" - "stream processing" researchr: "https://researchr.org/publication/MullerTA09" cites: 18 citedby: 6 journal: "PVLDB" volume: "2" number: "1" pages: "229-240" kind: "article" key: "MullerTA09" - title: "FPGAs: a new point in the database design space" author: - name: "René Müller" link: "http://www.systems.ethz.ch/people/muellren" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2010" doi: "http://doi.acm.org/10.1145/1739041.1739137" abstract: "In line with the insight that “one size” of databases will not fit all application needs, the database community is currently exploring various alternatives to commodity, CPU-based system designs. One particular candidate in this trend are field-programmable gate arrays (FPGAs), programmable chips that allow tailor-made hardware designs optimized for specific systems, applications, or even user queries. With a focus on database use, this tutorial introduces into FPGA technology, demonstrates its potential, but also pinpoints some challenges that need to be addressed before FPGA-accelerated database systems can go mainstream. The goal of this tutorial is to develop an intuition of an FPGA development cycle, receive guidelines for a “good” FPGA design, but also learn the limitations that hardware-implemented database processing faces. Our more high-level ambition is to spur a broader interest in database processing on novel hardware technology." links: doi: "http://doi.acm.org/10.1145/1739041.1739137" tags: - "FPGA" - "optimization" - "tutorial" - "rule-based" - "hardware-acceleration" - "database" - "program optimization" - "design" researchr: "https://researchr.org/publication/MullerT10" cites: 17 citedby: 0 pages: "721-723" booktitle: "EDBT 2010, 13th International Conference on Extending Database Technology, Lausanne, Switzerland, March 22-26, 2010, Proceedings" editor: - name: "Ioana Manolescu" link: "https://researchr.org/alias/ioana-manolescu" - name: "Stefano Spaccapietra" link: "https://researchr.org/alias/stefano-spaccapietra" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" - name: "Masaru Kitsuregawa" link: "https://researchr.org/alias/masaru-kitsuregawa" - name: "Alain Léger" link: "https://researchr.org/alias/alain-l%C3%A3%C2%A9ger" - name: "Felix Naumann" link: "https://researchr.org/alias/felix-naumann" - name: "Anastasia Ailamaki" link: "https://researchr.org/alias/anastasia-ailamaki" - name: "Fatma Özcan" link: "https://researchr.org/alias/fatma-%C3%A3%E2%80%93zcan" volume: "426" series: "ACM International Conference Proceeding Series" publisher: "ACM" isbn: "978-1-60558-945-9" kind: "inproceedings" key: "MullerT10" - title: "Bridging the GAP Between Relational and Native XML Storage with Staircase Join" author: - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" - name: "Torsten Grust" link: "http://www-db.informatik.uni-tuebingen.de/team/grust" - name: "Maurice van Keulen" link: "http://www.vf.utwente.nl/~keulen/" year: "2003" tags: - "XML" - "XML Schema" researchr: "https://researchr.org/publication/TeubnerGK03" cites: 0 citedby: 0 pages: "85-89" booktitle: "Tagungsband zum 15. GI-Workshop Grundlagen von Datenbanken, Tangermünde, Sachsen-Anhalt, 10.-13. Juni 2003" editor: - name: "Hagen Höpfner" link: "https://researchr.org/alias/hagen-h%C3%B6pfner" - name: "Gunter Saake" link: "https://researchr.org/alias/gunter-saake" - name: "Eike Schallehn" link: "https://researchr.org/alias/eike-schallehn" publisher: "Fakultät für Informatik, Universität Magdeburg" kind: "inproceedings" key: "TeubnerGK03" - title: "Staircase Join: Teach a Relational DBMS to Watch its (Axis) Steps" author: - name: "Torsten Grust" link: "http://www-db.informatik.uni-tuebingen.de/team/grust" - name: "Maurice van Keulen" link: "http://www.vf.utwente.nl/~keulen/" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2003" doi: "http://www.vldb.org/conf/2003/papers/S16P03.pdf" links: doi: "http://www.vldb.org/conf/2003/papers/S16P03.pdf" tags: - "staircase join" - "XPath" researchr: "https://researchr.org/publication/GrustKT03" cites: 0 citedby: 6 pages: "524-525" booktitle: "VLDB 2003, Proceedings of 29th International Conference on Very Large Data Bases, September 9-12, 2003, Berlin, Germany" editor: - name: "Johann Christoph Freytag" link: "https://researchr.org/alias/johann-christoph-freytag" - name: "Peter C. Lockemann" link: "https://researchr.org/alias/peter-c.-lockemann" - name: "Serge Abiteboul" link: "https://researchr.org/alias/serge-abiteboul" - name: "Michael J. Carey" link: "https://researchr.org/alias/michael-j.-carey" - name: "Patricia G. Selinger" link: "https://researchr.org/alias/patricia-g.-selinger" - name: "Andreas Heuer" link: "https://researchr.org/alias/andreas-heuer" publisher: "Morgan Kaufmann" isbn: "0-12-722442-4" kind: "inproceedings" key: "GrustKT03" - title: "Complex Event Detection at Wire Speed with FPGAs" author: - name: "Louis Woods" link: "http://www.systems.ethz.ch/people/lwoods" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" - name: "Gustavo Alonso" link: "http://www.systems.ethz.ch/people/alonso" year: "2010" doi: "http://www.comp.nus.edu.sg/~vldb2010/proceedings/files/papers/R59.pdf" abstract: "Complex event detection is an advanced form of data stream processing where the stream(s) are scrutinized to identify given event patterns. The challenge for many complex event processing (CEP) systems is to be able to evaluate event patterns on high-volume data streams while adhering to real-time constraints. To solve this problem, in this paper we present a hardware-based complex event detection system implemented on field-programmable gate arrays (FPGAs). By inserting the FPGA directly into the data path between the network interface and the CPU, our solution can detect complex events at gigabit wire speed with constant and fully predictable latency, independently of network load, packet size, or data distribution. This is a significant improvement over CPU-based systems and an architectural approach that opens up interesting opportunities for hybrid stream engines that combine the flexibility of the CPU with the parallelism and processing power of FPGAs. " links: doi: "http://www.comp.nus.edu.sg/~vldb2010/proceedings/files/papers/R59.pdf" dblp: "http://dblp.uni-trier.de/rec/bibtex/journals/pvldb/WoodsTA10" tags: - "FPGA" - "complex event processing" - "rule-based" - "architecture" - "constraints" - "data-flow programming" - "data-flow" - "source-to-source" - "pattern matching" - "pipelining" - "systematic-approach" - "open-source" - "stream processing" researchr: "https://researchr.org/publication/WoodsTA10" cites: 21 citedby: 1 journal: "PVLDB" volume: "3" number: "1" pages: "660-669" kind: "article" key: "WoodsTA10" - title: "Real-time pattern matching with FPGAs" author: - name: "Louis Woods" link: "http://www.systems.ethz.ch/people/lwoods" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" - name: "Gustavo Alonso" link: "http://www.systems.ethz.ch/people/alonso" year: "2011" doi: "http://dx.doi.org/10.1109/ICDE.2011.5767937" abstract: "We demonstrate a hardware implementation of a complex event processor, built on top of field-programmable gate arrays (FPGAs). Compared to CPU-based commodity systems, our solution shows distinctive advantages for stream monitoring tasks, e.g., wire-speed processing and predictable performance. The demonstration is based on a query-to-hardware compiler for complex event patterns that we presented at VLDB 2010. By example of a click stream monitoring application, we illustrate the inner workings of our compiler and indicate how FPGAs can act as efficient and reliable processors for event streams. " links: doi: "http://dx.doi.org/10.1109/ICDE.2011.5767937" dblp: "http://dblp.uni-trier.de/rec/bibtex/conf/icde/WoodsTA11" tags: - "rule-based" - "process monitoring" - "pattern matching" - "compiler" - "stream processing" researchr: "https://researchr.org/publication/WoodsTA11" cites: 9 citedby: 0 pages: "1292-1295" booktitle: "Proceedings of the 27th International Conference on Data Engineering, ICDE 2011, April 11-16, 2011, Hannover, Germany" editor: - name: "Serge Abiteboul" link: "https://researchr.org/alias/serge-abiteboul" - name: "Klemens Böhm" link: "https://researchr.org/alias/klemens-b%26ouml%3Bhm" - name: "Christoph Koch" link: "https://researchr.org/alias/christoph-koch" - name: "Kian-Lee Tan" link: "https://researchr.org/alias/kian-lee-tan" publisher: "IEEE Computer Society" isbn: "978-1-4244-8958-9" kind: "inproceedings" key: "WoodsTA11" - title: "Pathfinder: XQuery Compilation Techniques for Relational Database Targets" author: - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2007" doi: "http://www.btw2007.de/paper/p465.pdf" abstract: "Relational database systems are highly efficient hosts to table-shaped data. It is all the more interesting to see how a careful inspection of both, the XML tree structure as well as the W3C XQuery language definition, can turn relational databases into fast and scalable XML processors. This work shows how the deliberate choice of a relational tree encoding makes the XML data model―ordered, unranked trees―accessible to relational database systems. Efficient XPath-based access to these data is enabled in terms of staircase join, a join operator that injects full tree awareness into the relational database kernel. A loop-lifting compiler translates XQuery expressions into purely algebraic query plans. The representation of iteration (i.e., the XQuery FLWOR construct) in terms of set-oriented algebra primitives forms the core of this compiler. Together, the techniques we describe lead to unprecedented XQuery evaluation scalability in the multi-gigabyte XML range. Pathfinder is an open-source implementation of a purely relational XQuery processor. " links: doi: "http://www.btw2007.de/paper/p465.pdf" tags: - "relational data base" - "rule-based" - "staircase join" - "XQuery" - "translation" - "Loop Lifting" - "data-flow language" - "relational database" - "meta-model" - "XML" - "modeling language" - "XML Schema" - "language modeling" - "process algebra" - "XPath" - "relational algebra" - "data-flow" - "XPath Accelerator" - "source-to-source" - "compiler" - "tree encoding" - " algebra" - "database" - "context-aware" - "Meta-Environment" - "process modeling" - "open-source" - "query language" researchr: "https://researchr.org/publication/Teubner07" cites: 15 citedby: 0 pages: "465-474" booktitle: "Datenbanksysteme in Business, Technologie und Web (BTW 2007), 12. Fachtagung des GI-Fachbereichs Datenbanken und Informationssysteme (DBIS), Proceedings, 7.-9. März 2007, Aachen, Germany" editor: - name: "Alfons Kemper" link: "https://researchr.org/alias/alfons-kemper" - name: "Harald Schöning" link: "https://researchr.org/alias/harald-sch%C3%B6ning" - name: "Thomas Rose" link: "https://researchr.org/alias/thomas-rose" - name: "Matthias Jarke" link: "https://researchr.org/alias/matthias-jarke" - name: "Thomas Seidl" link: "https://researchr.org/alias/thomas-seidl" - name: "Christoph Quix" link: "https://researchr.org/alias/christoph-quix" - name: "Christoph Brochhaus" link: "https://researchr.org/alias/christoph-brochhaus" volume: "103" series: "LNI" publisher: "GI" isbn: "978-3-88579-197-3" kind: "inproceedings" key: "Teubner07" - title: "Pathfinder: XQuery Compilation Techniques for Relational Database Targets" author: - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2006" month: "October" doi: "http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:91-diss20061115-0920351297" abstract: "Even after at least a decade of work on XML and semi-structured information, such data is still predominantly processed in main-memory, which obviously leads to significant constraints for growing XML document sizes. On the other hand, mature database technologies are readily available to handle vast amounts of data easily. The most efficient ones, relational database management systems (RDBMSs), however, are largely locked-in to the processing of very regular, table-shaped data only. In this thesis, we will unleash the power of relational database technology to the domain of semi-structured data, the world of XML. We will present a purely relational XQuery processor that handles huge amounts of XML data in an efficient and scalable manner. Our setup is based on a relational tree encoding. The XPath accelerator, also known as pre/post numbering, has since become a widely accepted means to efficiently store XML data in a relational system. Yet, it has turned out that there is additional performance to gain. A close look into the encoding itself and the deliberate choice of relational indexes will give intriguing insights into the efficient access to node-based tree encodings. The backbone of XML query processing, the access to XML document regions in terms of XPath tree navigation, becomes particularly efficient if the database system is equipped with enhanced, tree-aware algorithms. We will devise staircase join, a novel join operator that encapsulates knowledge on the underlying tree encoding to provide efficient support for XPath navigation primitives. The required changes to the DBMS kernel remain remarkably small: staircase join integrates well with existing features of relational systems and comes at the cost of adding a single join operator only. The impact on performance, however, is significant: we observed speedups of several orders of magnitude on large-scale XML instances. Although existing XQuery processors make use of the resulting XPath performance gain by evaluating XPath navigation steps in the DBMS back-end, they tend to perform other core XQuery operations outside the relational database kernel. Most notably this affects the FLWOR iteration primitive, XQuery's node construction facilities, and the dynamic type semantics of XQuery. The loop-lifting technique we present in this work deals with these aspects in a purely relational fashion. The outcome is a loop-lifting compiler that translates arbitrary XQuery expressions into a single relational query plan. Generated plans take particular advantage of the operations that relational databases know how to perform best: relational joins as well as the computation of aggregates. The MonetDB/XQuery system to which this thesis has contributed provides the experimental proof of the effectiveness of our approach. MonetDB/XQuery is one of the fastest and most scalable XQuery engines available today and handles queries in the multi-gigabyte range in interactive time. The key to this performance are the techniques described in this thesis. They form the basis for MonetDB/XQuery's core component: the XQuery compiler Pathfinder. " links: doi: "http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:91-diss20061115-0920351297" tags: - "semantics" - "relational data base" - "rule-based" - "staircase join" - "XQuery" - "translation" - "Loop Lifting" - "relational XQuery" - "relational database" - "memory management" - "XML" - "XML Schema" - "XPath" - "constraints" - "type system" - "data-flow" - "XPath Accelerator" - "compiler" - "database" - "context-aware" - "data encapsulation" - "systematic-approach" researchr: "https://researchr.org/publication/TeubnerPhD" cites: 0 citedby: 1 school: "Technische Universität München" advisor: - name: "Torsten Grust" link: "http://www-db.informatik.uni-tuebingen.de/team/grust" kind: "phdthesis" key: "TeubnerPhD" - title: "Frequent Item Computation on a Chip" author: - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" - name: "René Müller" link: "http://www.systems.ethz.ch/people/muellren" - name: "Gustavo Alonso" link: "http://www.systems.ethz.ch/people/alonso" year: "2011" doi: "http://dx.doi.org/10.1109/TKDE.2010.216" abstract: "Computing frequent items is an important problem by itself and as a sub-routine in several data mining algorithms. In this paper we explore how to accelerate the computation of frequent items using field-programmable gate arrays (FPGAs) with a threefold goal: increase performance over existing solutions, reduce energy consumption over CPU-based systems, and explore the design space in detail as the constraints on FPGAs are very different from those of traditional software-based systems. We discuss three design alternatives, each one of them exploiting different FPGA features and each one providing different performance/scalability trade-offs. An important result of the paper is to demonstrate how the inherent massive parallelism of FPGAs can improve performance of existing algorithms but only after a fundamental redesign of the algorithms. Our experimental results show that, e.g., the pipelined solution we introduce can reach more than 100 million tuples per second of sustained throughput (four times the best available results to date) by making use of techniques that are not available to CPU-based solutions. Moreover, and unlike in software approaches, the high throughput is independent of the skew of the Zipf distribution of the input and at a far lower energy cost. " links: doi: "http://dx.doi.org/10.1109/TKDE.2010.216" dblp: "http://dblp.uni-trier.de/rec/bibtex/journals/tkde/TeubnerMA11" tags: - "rule-based" - "constraints" - "data-flow programming" - "data-flow" - "design" - "systematic-approach" researchr: "https://researchr.org/publication/TeubnerMA11" cites: 21 citedby: 0 journal: "IEEE Trans. Knowl. Data Eng." volume: "23" number: "8" pages: "1169-1181" kind: "article" key: "TeubnerMA11" - title: "An Injection of Tree Awareness: Adding Staircase Join to PostgreSQL" author: - name: "Sabine Mayer" link: "https://researchr.org/profile/sabinemayer/publications" - name: "Torsten Grust" link: "http://www-db.informatik.uni-tuebingen.de/team/grust" - name: "Maurice van Keulen" link: "http://www.vf.utwente.nl/~keulen/" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2004" doi: "http://www.vldb.org/conf/2004/DEMP14.PDF" links: doi: "http://www.vldb.org/conf/2004/DEMP14.PDF" tags: - "staircase join" - "PostgreSQL" - "XPath" - "context-aware" researchr: "https://researchr.org/publication/MayerGKT04" cites: 0 citedby: 3 pages: "1305-1308" booktitle: "(e)Proceedings of the Thirtieth International Conference on Very Large Data Bases, Toronto, Canada, August 31 - September 3 2004" editor: - name: "Mario A. Nascimento" link: "https://researchr.org/alias/mario-a.-nascimento" - name: "M. Tamer Özsu" link: "https://researchr.org/alias/m.-tamer-%C3%B6zsu" - name: "Donald Kossmann" link: "https://researchr.org/alias/donald-kossmann" - name: "Renée J. Miller" link: "https://researchr.org/alias/ren%C3%A9e-j.-miller" - name: "José A. Blakeley" link: "https://researchr.org/alias/jos%C3%A9-a.-blakeley" - name: "K. Bernhard Schiefer" link: "https://researchr.org/alias/k.-bernhard-schiefer" publisher: "Morgan Kaufmann" isbn: "0-12-088469-0" kind: "inproceedings" key: "MayerGKT04" - title: "FPGA: What's in it for a Database?" author: - name: "Rene Mueller" link: "http://people.inf.ethz.ch/muellren/" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2009" doi: "http://doi.acm.org/10.1145/1559845.1559965" abstract: "While there seems to be a general agreement that next years' systems will include many processing cores, it is often overlooked that these systems will also include an increasing number of different cores (we already see dedicated units for graphics or network processing). Orchestrating the diversity of processing functionality is going to be a major challenge in the upcoming years, be it to optimize for performance or for minimal energy consumption. We expect field-programmable gate arrays (FPGAs or “programmable hardware”) to soon play the role of yet another processing unit, found in commodity computers. It is clear that the new resource is going to be too precious to be ignored by database systems, but it is unclear how FPGAs could be integrated into a DBMS. With a focus on database use, this tutorial introduces into the emerging technology, demonstrates its potential, but also pinpoints some chal- lenges that need to be addressed before FPGA-accelerated database systems can go mainstream. Attendees will gain an intuition of an FPGA development cycle, receive guidelines for a “good” FPGA design, but also learn the limitations that hardware-implemented database processing faces. Our more high-level ambition is to spur a broader interest in database processing on novel hardware technology. " links: doi: "http://doi.acm.org/10.1145/1559845.1559965" tags: - "FPGA" - "optimization" - "functional programming" - "database" - "program optimization" - "design" researchr: "https://researchr.org/publication/MuellerT09" cites: 21 citedby: 0 pages: "999-1004" booktitle: "Proceedings of the ACM SIGMOD International Conference on Management of Data, SIGMOD 2009, Providence, Rhode Island, USA, June 29 - July 2, 2009" editor: - name: "Ugur Çetintemel" link: "https://researchr.org/alias/ugur-%C3%A7etintemel" - name: "Stanley B. Zdonik" link: "https://researchr.org/alias/stanley-b.-zdonik" - name: "Donald Kossmann" link: "https://researchr.org/alias/donald-kossmann" - name: "Nesime Tatbul" link: "https://researchr.org/alias/nesime-tatbul" publisher: "ACM" isbn: "978-1-60558-551-2" kind: "inproceedings" key: "MuellerT09" - title: "Glacier: a query-to-hardware compiler" author: - name: "René Müller" link: "http://www.systems.ethz.ch/people/muellren" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" - name: "Gustavo Alonso" link: "http://www.systems.ethz.ch/people/alonso" year: "2010" doi: "http://doi.acm.org/10.1145/1807167.1807307" abstract: "Field-programmable gate arrays (FPGAs) are a promising technology that can be used in database systems. In this demonstration we show Glacier, a library and a compiler that can be employed to implement streaming queries as hardware circuits on FPGAs. Glacier consists of a library of compositional hardware modules that represent stream processing operators. Given a query execution plan, the compiler instantiates the corresponding components and wires them up to a digital circuit. The goal of this demo is to show the flexibility of the compositional approach. " links: doi: "http://doi.acm.org/10.1145/1807167.1807307" dblp: "http://dblp.uni-trier.de/rec/bibtex/conf/sigmod/MullerTA10" tags: - "FPGA" - "SQL-to-Hardware" - "SQL" - "digital library" - "composition" - "source-to-source" - "digital libraries" - "compiler" - "database" - "systematic-approach" - "open-source" - "stream processing" researchr: "https://researchr.org/publication/MullerTA10" cites: 8 citedby: 0 pages: "1159-1162" booktitle: "Proceedings of the ACM SIGMOD International Conference on Management of Data, SIGMOD 2010, Indianapolis, Indiana, USA, June 6-10, 2010" editor: - name: "Ahmed K. Elmagarmid" link: "https://researchr.org/alias/ahmed-k.-elmagarmid" - name: "Divyakant Agrawal" link: "https://researchr.org/alias/divyakant-agrawal" publisher: "ACM" isbn: "978-1-4503-0032-2" kind: "inproceedings" key: "MullerTA10" - title: "Scalable XQuery Type Matching" author: - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2008" doi: "http://doi.acm.org/10.1145/1353343.1353353" abstract: "XML Schema awareness has been an integral part of the XQuery language since its early design stages. Matching XML data against XML types is the main operation that backs up XQuery type expressions, such as typeswitch, instance of, or certain XPath operators. This interaction is particularly vital in data-centric XQuery applications, where data come with detailed type information from an XML Schema document. So far there has been little work on the optimization of those operations. This work presents an efficient implementation of the runtime aspects of XML Schema support. We propose type ranks as a novel and uniform way to implement all facets of type matching in the W3C XQuery Recommendation. As a concise encoding of the type hierarchy defined by an XML Schema document, type ranks minimize the cost of checking the runtime type of XQuery singleton items. By aggregating type ranks, we leverage the grouping capabilities of modern DBMS implementations to efficiently execute type matching on XQuery sequences. In addition, we improve the complexity bounds incurring with typeswitch expressions over existing approaches. Experiments on an off-the-shelf database system demonstrate the potential of our approach." links: doi: "http://doi.acm.org/10.1145/1353343.1353353" tags: - "optimization" - "interaction design" - "XQuery" - "data-flow language" - "dynamic typing" - "XML" - "XML Schema" - "design complexity" - "XPath" - "language design" - "type system" - "little language" - "data-flow" - "type checking" - "database" - "context-aware" - "design" - "type matching" - "systematic-approach" researchr: "https://researchr.org/publication/Teubner08" cites: 19 citedby: 2 pages: "38-48" booktitle: "EDBT 2008, 11th International Conference on Extending Database Technology, Nantes, France, March 25-29, 2008, Proceedings" editor: - name: "Alfons Kemper" link: "https://researchr.org/alias/alfons-kemper" - name: "Patrick Valduriez" link: "https://researchr.org/alias/patrick-valduriez" - name: "Noureddine Mouaddib" link: "https://researchr.org/alias/noureddine-mouaddib" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" - name: "Mokrane Bouzeghoub" link: "https://researchr.org/alias/mokrane-bouzeghoub" - name: "Volker Markl" link: "https://researchr.org/alias/volker-markl" - name: "Laurent Amsaleg" link: "https://researchr.org/alias/laurent-amsaleg" - name: "Ioana Manolescu" link: "https://researchr.org/alias/ioana-manolescu" volume: "261" series: "ACM International Conference Proceeding Series" publisher: "ACM" isbn: "978-1-59593-926-5" kind: "inproceedings" key: "Teubner08" - title: "eXrQuy: Order Indifference in XQuery" author: - name: "Torsten Grust" link: "http://www-db.informatik.uni-tuebingen.de/team/grust" - name: "Jan Rittinger" link: "http://www-db.informatik.uni-tuebingen.de/team/rittinger" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2007" doi: "http://dx.doi.org/10.1109/ICDE.2007.367868" abstract: "There are more spots than immediately obvious in XQuery expressions where order is immaterial for evaluation―this affects most notably, but not exclusively, expressions in the scope of unordered { } and the argument of fn:unordered(). Clearly, performance gains are lurking behind such expression contexts but the prevalent impact of order on the XQuery semantics reaches deep into any compliant XQuery processor, making it non-trivial to set this potential free. Here, we describe how the relational XQuery compiler Pathfinder uniformly exploits such order indifference in a purely algebraic fashion: Pathfinder-emitted plans faithfully implement the required XQuery order semantics but (locally) ignore order wherever this is admitted." links: doi: "http://dx.doi.org/10.1109/ICDE.2007.367868" tags: - "semantics" - "XQuery" - "process algebra" - "relational algebra" - "compiler" - " algebra" - "context-aware" researchr: "https://researchr.org/publication/GrustRT07" cites: 19 citedby: 5 pages: "226-235" booktitle: "Proceedings of the 23rd International Conference on Data Engineering, ICDE 2007, April 15-20, 2007, The Marmara Hotel, Istanbul, Turkey" publisher: "IEEE" kind: "inproceedings" key: "GrustRT07" - title: "How soccer players would do stream joins" author: - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" - name: "René Müller" link: "http://www.systems.ethz.ch/people/muellren" year: "2011" doi: "http://doi.acm.org/10.1145/1989323.1989389" abstract: "In spite of the omnipresence of parallel (multi-core) systems, the predominant strategy to evaluate window-based stream joins is still strictly sequential, mostly just straightforward along the definition of the operation semantics. In this work we present handshake join, a way of describing and executing window-based stream joins that is highly amenable to parallelized execution. Handshake join naturally leverages available hardware parallelism, which we demonstrate with an implementation on a modern multi-core system and on top of field-programmable gate arrays (FPGAs), an emerging technology that has shown distinctive advantages for high-throughput data processing. On the practical side, we provide a join implementation that substantially outperforms CellJoin (the fastest published result) and that will directly turn any degree of parallelism into higher throughput or larger supported window sizes. On the semantic side, our work gives a new intuition of window semantics, which we believe could inspire other stream processing algorithms or ongoing standardization efforts for stream query languages. " links: doi: "http://doi.acm.org/10.1145/1989323.1989389" dblp: "http://dblp.uni-trier.de/rec/bibtex/conf/sigmod/TeubnerM11" tags: - "programming languages" - "semantics" - "rule-based" - "data-flow language" - "stream join" - "handshake join" - "parallelism" - "parallel programming" - "data-flow programming" - "data-flow" - "stream processing" - "query language" - "multi-core" researchr: "https://researchr.org/publication/TeubnerM11" cites: 30 citedby: 0 pages: "625-636" booktitle: "Proceedings of the ACM SIGMOD International Conference on Management of Data, SIGMOD 2011, Athens, Greece, June 12-16, 2011" editor: - name: "Timos K. Sellis" link: "https://researchr.org/alias/timos-k.-sellis" - name: "Renée J. Miller" link: "https://researchr.org/alias/ren%26eacute%3Be-j.-miller" - name: "Anastasios Kementsietsidis" link: "https://researchr.org/alias/anastasios-kementsietsidis" - name: "Yannis Velegrakis" link: "https://researchr.org/alias/yannis-velegrakis" publisher: "ACM" isbn: "978-1-4503-0661-4" kind: "inproceedings" key: "TeubnerM11" - title: "MonetDB/XQuery: a fast XQuery processor powered by a relational engine" author: - name: "Peter A. Boncz" link: "http://homepages.cwi.nl/~boncz/" - name: "Torsten Grust" link: "http://www-db.informatik.uni-tuebingen.de/team/grust" - name: "Maurice van Keulen" link: "http://www.vf.utwente.nl/~keulen/" - name: "Stefan Manegold" link: "http://homepages.cwi.nl/~manegold/" - name: "Jan Rittinger" link: "http://www-db.informatik.uni-tuebingen.de/team/rittinger" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2006" doi: "http://doi.acm.org/10.1145/1142473.1142527" abstract: "Relational XQuery systems try to re-use mature relational data management infrastructures to create fast and scalable XML database technology. This paper describes the main features, key contributions, and lessons learned while implementing such a system. Its architecture consists of (i) a range-based encoding of XML documents into relational tables, (ii) a compilation technique that translates XQuery into a basic relational algebra, (iii) a restricted (order) property-aware peephole relational query optimization strategy, and (iv) a mapping from XML update statements into relational updates. Thus, this system implements all essential XML database functionalities (rather than a single feature) such that we can learn from the full consequences of our architectural decisions. While implementing this system, we had to extend the state-of-the- art with a number of new technical contributions, such as loop-lifted staircase join and efficient relational query evaluation strategies for XQuery theta-joins with existential semantics. These contributions as well as the architectural lessons learned are also deemed valuable for other relational back-end engines. The performance and scalability of the resulting system is evaluated on the XMark benchmark up to data sizes of 11 GB. The performance section also provides an extensive comparison of all major XMark results published previously, which confirm that the goal of purely relational XQuery processing, namely speed and scalability, was met." links: doi: "http://doi.acm.org/10.1145/1142473.1142527" tags: - "optimization" - "semantics" - "relational data base" - "rule-based" - "staircase join" - "XQuery" - "translation" - "Loop Lifting" - "relational database" - "XML" - "XML Schema" - "architecture" - "process algebra" - "XPath" - "relational algebra" - "data-flow" - " algebra" - "database" - "context-aware" - "MonetDB/XQuery" researchr: "https://researchr.org/publication/BonczGKMRT06" cites: 0 citedby: 9 pages: "479-490" booktitle: "Proceedings of the ACM SIGMOD International Conference on Management of Data, Chicago, Illinois, USA, June 27-29, 2006" editor: - name: "Surajit Chaudhuri" link: "https://researchr.org/alias/surajit-chaudhuri" - name: "Vagelis Hristidis" link: "https://researchr.org/alias/vagelis-hristidis" - name: "Neoklis Polyzotis" link: "https://researchr.org/alias/neoklis-polyzotis" publisher: "ACM" isbn: "1-59593-256-9" kind: "inproceedings" key: "BonczGKMRT06" - title: "Why off-the-shelf RDBMSs are better at XPath than you might expect" author: - name: "Torsten Grust" link: "http://www-db.informatik.uni-tuebingen.de/team/grust" - name: "Jan Rittinger" link: "http://www-db.informatik.uni-tuebingen.de/team/rittinger" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2007" doi: "http://doi.acm.org/10.1145/1247480.1247591" abstract: "To compensate for the inherent impedance mismatch between the relational data model (tables of tuples) and XML (ordered, unranked trees), tree join algorithms have become the prevalent means to process XML data in relational databases, most notably the TwigStack, structural join, and staircase join algorithms. However, the addition of these algorithms to existing systems depends on a significant invasion of the underlying database kernel, an option intolerable for most database vendors. Here, we demonstrate that we can achieve comparable XPath performance without touching the heart of the system. We carefully exploit existing database functionality and accelerate XPath navigation by purely relational means: partitioned B-trees bring access costs to secondary storage to a minimum, while aggregation functions avoid an expensive computation and removal of duplicate result nodes to comply with the XPath semantics. Experiments carried out on IBM DB2 confirm that our approach can turn off-the-shelf database systems into efficient XPath processors." links: doi: "http://doi.acm.org/10.1145/1247480.1247591" tags: - "semantics" - "relational database" - "meta-model" - "XML" - "XML Schema" - "Partitioned B-trees" - "XPath" - "data-flow" - "database" - "Meta-Environment" - "partitioning" - "process modeling" - "systematic-approach" researchr: "https://researchr.org/publication/GrustRT07%3A0" cites: 0 citedby: 4 pages: "949-958" booktitle: "Proceedings of the ACM SIGMOD International Conference on Management of Data, Beijing, China, June 12-14, 2007" editor: - name: "Chee Yong Chan" link: "https://researchr.org/alias/chee-yong-chan" - name: "Beng Chin Ooi" link: "https://researchr.org/alias/beng-chin-ooi" - name: "Aoying Zhou" link: "https://researchr.org/alias/aoying-zhou" publisher: "ACM" isbn: "978-1-59593-686-8" kind: "inproceedings" key: "GrustRT07:0" - title: "Data-intensive XQuery debugging with instant replay" author: - name: "Torsten Grust" link: "http://www-db.informatik.uni-tuebingen.de/team/grust" - name: "Jan Rittinger" link: "http://www-db.informatik.uni-tuebingen.de/team/rittinger" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2007" doi: "http://doi.acm.org/10.1145/1328158.1328162" abstract: "We explore the design and implementation of Rover, a postmortem debugger for XQuery. Rather than being based on the traditional breakpoint model, Rover acknowledges XQuery's nature as a functional language: the debugger follows a declarative debugging paradigm in which a user is enabled to observe the values of selected XQuery subexpressions. Rover has been designed to hook into Pathfinder, an XQuery compiler that emits relational algebra plans for evaluation on commodity relational database back-ends. The debugger instruments the subject query with fn:trace() calls which, at query runtime, populate database tables with relational representations of XQuery item sequences. Thanks to Pathfinder's loop-lifting compilation strategy, a Rover trace (1) may span multiple XQuery for iteration scopes and (2) allows for interactive debugging sessions that can arbitrarily replay iterations in a unique forward/backward fashion. Since the query runtime as well as the debugger are database-supported, Rover is scalable and supports the observation of very data-intensive XQuery expressions." links: doi: "http://doi.acm.org/10.1145/1328158.1328162" tags: - "relational data base" - "rule-based" - "XQuery" - "data-flow language" - "relational database" - "meta-model" - "modeling language" - "language modeling" - "relational algebra" - "language design" - "data-flow" - "debugging" - "compiler" - " algebra" - "database" - "Meta-Environment" - "design" - "query language" researchr: "https://researchr.org/publication/GrustRT07%3A1" cites: 0 citedby: 0 booktitle: "Proceedings of the 4th International Workshop on XQuery Implementation, Experience and Perspectives, in cooperation with ACM SIGMOD, June 15, 2007, Beijing, China" editor: - name: "Jayavel Shanmugasundaram" link: "https://researchr.org/alias/jayavel-shanmugasundaram" - name: "Jérôme Siméon" link: "https://researchr.org/alias/j%C3%A9r%C3%B4me-sim%C3%A9on" isbn: "978-1-59593-800-8" kind: "inproceedings" key: "GrustRT07:1" - title: "Relational Algebra: Mother Tongue - XQuery: Fluent" author: - name: "Torsten Grust" link: "http://www-db.informatik.uni-tuebingen.de/team/grust" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" year: "2004" doi: "http://www.ctit.utwente.nl/library/proceedings/tdm04.pdf" links: doi: "http://www.ctit.utwente.nl/library/proceedings/tdm04.pdf" tags: - "XQuery" - "Loop Lifting" - "relational algebra" - "compiler" - " algebra" researchr: "https://researchr.org/publication/GrustT04" cites: 0 citedby: 6 pages: "9-16" booktitle: "First Twente Data Management Workshop (TDM 2004) on XML Databases and Information Retrieval, Enschede, The Netherlands, June 21, 2004" editor: - name: "Vojkan Mihajlovic" link: "https://researchr.org/alias/vojkan-mihajlovic" - name: "Djoerd Hiemstra" link: "https://researchr.org/alias/djoerd-hiemstra" series: "CTIT Workshop Proceedings Series" publisher: "Centre for Telematics and Information Technology (CTIT), University of Twente, Enschede, The Netherlands" kind: "inproceedings" key: "GrustT04" - title: "High-Performance Thermoelectric Tl9BiTe6 with an Extremely Low Thermal Conductivity" author: - name: "Bernd Wölfing" link: "https://researchr.org/profile/berndwlfing/publications" - name: "Christian Kloc" link: "http://www.mse.ntu.edu.sg/AboutUs/Organisation/Pages/ckloc.aspx" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" - name: "Ernst Bucher" link: "https://researchr.org/profile/ernstbucher/publications" year: "2001" month: "May" doi: "http://link.aps.org/doi/10.1103/PhysRevLett.86.4350" abstract: "Tl9BiTe6 exhibits a thermoelectric figure of merit of ZT∼1.2 around 500 K, which significantly exceeds the state-of-the-art materials in this temperature range. The extraordinary thermoelectric performance is mainly due to the extremely low thermal conductivity of Tl9BiTe6 [0.39 W/(ṁK) at 300 K]. In fact, the minimum lifetime of the phonons has to be taken into account to describe the thermal conductivity data." links: doi: "http://link.aps.org/doi/10.1103/PhysRevLett.86.4350" tags: - "data-flow" researchr: "https://researchr.org/publication/Wolfing01" cites: 0 citedby: 0 journal: "Physical Review Letters" volume: "86" number: "19" kind: "article" key: "Wolfing01" - title: "EDBT 2009, 12th International Conference on Extending Database Technology, Saint Petersburg, Russia, March 24-26, 2009, Proceedings" year: "2009" tags: - "database" researchr: "https://researchr.org/publication/edbt%3A2009" cites: 0 citedby: 0 booktitle: "EDBT 2009, 12th International Conference on Extending Database Technology, Saint Petersburg, Russia, March 24-26, 2009, Proceedings" conference: "edbt" editor: - name: "Martin L. Kersten" link: "https://researchr.org/alias/martin-l.-kersten" - name: "Boris Novikov" link: "https://researchr.org/alias/boris-novikov" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" - name: "Vladimir Polutin" link: "https://researchr.org/alias/vladimir-polutin" - name: "Stefan Manegold" link: "http://homepages.cwi.nl/~manegold/" volume: "360" series: "ACM International Conference Proceeding Series" publisher: "ACM" isbn: "978-1-60558-422-5" kind: "proceedings" key: "edbt:2009" - title: "EDBT 2008, 11th International Conference on Extending Database Technology, Nantes, France, March 25-29, 2008, Proceedings" year: "2008" tags: - "database" researchr: "https://researchr.org/publication/edbt%3A2008" cites: 0 citedby: 0 booktitle: "EDBT 2008, 11th International Conference on Extending Database Technology, Nantes, France, March 25-29, 2008, Proceedings" conference: "edbt" editor: - name: "Alfons Kemper" link: "https://researchr.org/alias/alfons-kemper" - name: "Patrick Valduriez" link: "https://researchr.org/alias/patrick-valduriez" - name: "Noureddine Mouaddib" link: "https://researchr.org/alias/noureddine-mouaddib" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" - name: "Mokrane Bouzeghoub" link: "https://researchr.org/alias/mokrane-bouzeghoub" - name: "Volker Markl" link: "https://researchr.org/alias/volker-markl" - name: "Laurent Amsaleg" link: "https://researchr.org/alias/laurent-amsaleg" - name: "Ioana Manolescu" link: "https://researchr.org/alias/ioana-manolescu" volume: "261" series: "ACM International Conference Proceeding Series" publisher: "ACM" isbn: "978-1-59593-926-5" kind: "proceedings" key: "edbt:2008" - title: "EDBT 2010, 13th International Conference on Extending Database Technology, Lausanne, Switzerland, March 22-26, 2010, Proceedings" year: "2010" tags: - "database" researchr: "https://researchr.org/publication/edbt-2010" cites: 0 citedby: 0 booktitle: "EDBT 2010, 13th International Conference on Extending Database Technology, Lausanne, Switzerland, March 22-26, 2010, Proceedings" conference: "edbt" editor: - name: "Ioana Manolescu" link: "https://researchr.org/alias/ioana-manolescu" - name: "Stefano Spaccapietra" link: "https://researchr.org/alias/stefano-spaccapietra" - name: "Jens Teubner" link: "http://people.inf.ethz.ch/jteubner/" - name: "Masaru Kitsuregawa" link: "https://researchr.org/alias/masaru-kitsuregawa" - name: "Alain Léger" link: "https://researchr.org/alias/alain-l%C3%A3%C2%A9ger" - name: "Felix Naumann" link: "https://researchr.org/alias/felix-naumann" - name: "Anastasia Ailamaki" link: "https://researchr.org/alias/anastasia-ailamaki" - name: "Fatma Özcan" link: "https://researchr.org/alias/fatma-%C3%A3%E2%80%93zcan" volume: "426" series: "ACM International Conference Proceeding Series" publisher: "ACM" isbn: "978-1-60558-945-9" kind: "proceedings" key: "edbt-2010"