Processing Joins With User-Defined Functions
Title | Processing Joins With User-Defined Functions |
Publication Type | Technical Report |
Year of Publication | 1994 |
Authors | Gaede, V., & Günther O. |
Other Numbers | 883 |
Keywords | extensible and object-oriented database systems, functional join, query optimization, query processing, user-defined predicates, z-ordering |
Abstract | Most strategies for the computation of relational joins (such as sort-merge or hash-join) are facing major difficulties if the join predicate involves complex, user-defined functions rather than just simple arithmetic comparisons. In this paper, we identify a class of user-defined functions that can be included in a join predicate, such that a join between two sets R and S can still be computed efficiently, i.e., in time significantly less than O(|R|x|S|). For that purpose, we introduce the notion of the phi-function, an operator to process each set element separately with respect to the user-defined function(s) being used. Then any particular join query containing those functions can be computed by a variation of some traditional join strategy. After demonstrating this technique on a spatial database example, we present the results of a theoretical analysis and a practical performance evaluation. |
URL | http://www.icsi.berkeley.edu/ftp/global/pub/techreports/1994/tr-94-013.pdf |
Bibliographic Notes | ICSI Technical Report TR-94-013 |
Abbreviated Authors | V. Gaede and O. Günther |
ICSI Publication Type | Technical Report |