Title
Rule languages and internal algebras for rule-based optimizers
Abstract
Rule-based optimizers and optimizer generators use rules to specify query transformations. Rules act directly on query representations, which typically are based on query algebras. But most algebras complicate rule formulation, and rules over these algebras must often resort to calling to externally defined bodies of code. Code makes rules difficult to formulate, prove correct and reason about, and therefore compromises the effectiveness of rule-based systems.In this paper we present KOLA: a combinator-based algebra designed to simplify rule formulation. KOLA is not a user language, and KOLA's variable-free queries are difficult for humans to read. But KOLA is an effective internal algebra because its combinator-style makes queries manipulable and structurally revealing. As a result, rules over KOLA queries are easily expressed without the need for supplemental code. We illustrate this point, first by showing some transformations that despite their simplicity, require head and body routines when expressed over algebras that include variables. We show that these transformations are expressible without supplemental routines in KOLA. We then show complex transformations of a class of nested queries expressed over KOLA. Nested query optimization, while having been studied before, have seriously challenged the rule-based paradigm.
Year
DOI
Venue
1996
10.1145/233269.233356
SIGMOD Conference
Keywords
Field
DocType
user defined functions,rule based,rule based system,query optimization
Query optimization,Data mining,Rule-based system,Programming language,Combinatory logic,Computer science,Theoretical computer science,User-defined function,Database,Content based analysis
Conference
Volume
Issue
ISBN
25
2
0-89791-794-4
Citations 
PageRank 
References 
23
7.68
23
Authors
2
Name
Order
Citations
PageRank
Mitch Cherniack14128293.66
Stanley B. Zdonik291861660.15