publications: - 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: "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: "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"