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Improved Unnesting Algorithms for Join Aggregate SQL Queries.

M. Muralikrishna: Improved Unnesting Algorithms for Join Aggregate SQL Queries. VLDB 1992: 91-102
@inproceedings{DBLP:conf/vldb/Muralikrishna92,
  author    = {M. Muralikrishna},
  editor    = {Li-Yan Yuan},
  title     = {Improved Unnesting Algorithms for Join Aggregate SQL Queries},
  booktitle = {18th International Conference on Very Large Data Bases, August
               23-27, 1992, Vancouver, Canada, Proceedings},
  publisher = {Morgan Kaufmann},
  year      = {1992},
  isbn      = {1-55860-151-1},
  pages     = {91-102},
  ee        = {db/conf/vldb/Muralikrishna92.html},
  crossref  = {DBLP:conf/vldb/92},
  bibsource = {DBLP, http://dblp.uni-trier.de}
}
BibTeX

Abstract

The SQL language allows users to express queries that have nested subqueries inthem. Optimization of nested queries has received considerable attention over the last few years [Kim82, Ganski87, Dayal87, Murali89]. As pointed out in [Ganski87], the solution presented in [Kim82] for JA type queries has the COUNT bug. In order to avoid the COUNT bug, the more general strategy described in [Ganski87] and [Dayal87] is used. In this paper, we modify Kim's algorithm so that it avoids the COUNT bug. The modified algorithm may be used when it is more efficient than the general strategy. In addition, we present a couple of enhancements that precompute aggregates andevaluate joins and outer joins in a top- down order. These enhancements eliminate Cartesian products when certain correlation predicates are absent and enable us to employ Kim's method for more blocks. Finally, we incorporate the above improvements into a new unnesting algorithm.

Copyright © 1992 by the VLDB Endowment. Permission to copy without fee all or part of this material is granted provided that the copies are not made or distributed for direct commercial advantage, the VLDB copyright notice and the title of the publication and its date appear, and notice is given that copying is by the permission of the Very Large Data Base Endowment. To copy otherwise, or to republish, requires a fee and/or special permission from the Endowment.


Online Paper

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Printed Edition

Li-Yan Yuan (Ed.): 18th International Conference on Very Large Data Bases, August 23-27, 1992, Vancouver, Canada, Proceedings. Morgan Kaufmann 1992, ISBN 1-55860-151-1
Contents BibTeX

References

[Astrahan75]
Morton M. Astrahan, Donald D. Chamberlin: Implementation of a Structured English Query Language. Commun. ACM 18(10): 580-588(1975) BibTeX
[Dayal87]
Umeshwar Dayal: Of Nests and Trees: A Unified Approach to Processing Queries That Contain Nested Subqueries, Aggregates, and Quantifiers. VLDB 1987: 197-208 BibTeX
[Epstein79]
...
[Ganski87]
Richard A. Ganski, Harry K. T. Wong: Optimization of Nested SQL Queries Revisited. SIGMOD Conference 1987: 23-33 BibTeX
[Kiessling84]
...
[Kim82]
Won Kim: On Optimizing an SQL-like Nested Query. ACM Trans. Database Syst. 7(3): 443-469(1982) BibTeX
[Murali89]
M. Muralikrishna: Optimization and Dataflow Algorithms for Nested Tree Queries. VLDB 1989: 77-85 BibTeX
[Rose90]
Arnon Rosenthal, César A. Galindo-Legaria: Query Graphs, Implementing Trees, and Freely-Reorderable Outerjoins. SIGMOD Conference 1990: 291-299 BibTeX

Referenced by

  1. Leonidas Fegaras: Query Unnesting in Object-Oriented Databases. SIGMOD Conference 1998: 49-60
  2. Surajit Chaudhuri: An Overview of Query Optimization in Relational Systems. PODS 1998: 34-43
  3. Pedro Celis, Hansjörg Zeller: Subquery Elimination: A Complete Unnesting Algorithm for an Extended Relational Algebra. ICDE 1997: 321
  4. William J. McKenna, Louis Burger, Chi Hoang, Melissa Truong: EROC: A Toolkit for Building NEATO Query Optimizers. VLDB 1996: 111-121
  5. Piyush Goel, Balakrishna R. Iyer: SQL Query Optimization: Reordering for a General Class of Queries. SIGMOD Conference 1996: 47-56
  6. Mitch Cherniack, Stanley B. Zdonik: Rule Languages and Internal Algebras for Rule-Based Optimizers. SIGMOD Conference 1996: 401-412
  7. Alon Y. Levy, Inderpal Singh Mumick: Reasoning with Aggregation Constraints. EDBT 1996: 514-534
  8. Surajit Chaudhuri, Kyuseok Shim: Optimizing Queries with Aggregate Views. EDBT 1996: 167-182
  9. Weiyi Meng, Clement T. Yu, Won Kim: A Theory of Translation From Relational Queries to Hierarchical Queries. IEEE Trans. Knowl. Data Eng. 7(2): 228-245(1995)
  10. Surajit Chaudhuri, Kyuseok Shim: An Overview of Cost-based Optimization of Queries with Aggregates. IEEE Data Eng. Bull. 18(3): 3-9(1995)
  11. Qi Yang, Chengwen Liu, Jing Wu, Clement T. Yu, Son Dao, Hiroshi Nakajima: Efficient Processing of Nested Fuzzy SQL Queries. ICDE 1995: 131-138
  12. Sophie Cluet, Guido Moerkotte: Efficient Evaluation of Aggregates on Bulk Types. DBPL 1995: 8
  13. Alon Y. Levy, Inderpal Singh Mumick, Yehoshua Sagiv: Query Optimization by Predicate Move-Around. VLDB 1994: 96-107
  14. Surajit Chaudhuri, Kyuseok Shim: Including Group-By in Query Optimization. VLDB 1994: 354-366
  15. Inderpal Singh Mumick, Hamid Pirahesh: Implementation of Magic-sets in a Relational Database System. SIGMOD Conference 1994: 103-114
  16. G. N. Paulley, Per-Åke Larson: Exploiting Uniqueness in Query Optimization. ICDE 1994: 68-79
  17. Hennie J. Steenhagen, Peter M. G. Apers, Henk M. Blanken: Optimization of Nested Queries in a Complex Object Model. EDBT 1994: 337-350
  18. José A. Blakeley, William J. McKenna, Goetz Graefe: Experiences Building the Open OODB Query Optimizer. SIGMOD Conference 1993: 287-296
  19. Weiyi Meng, Clement T. Yu, Won Kim, Gaoming Wang, Tracy Pham, Son Dao: Construction of a Relational Front-end for Object-Oriented Database Systems. ICDE 1993: 476-483
  20. Sophie Cluet, Guido Moerkotte: Nested Queries in Object Bases. DBPL 1993: 226-242
BibTeX
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