University of Florida :: Department of Computer and Information Science and Engineering (CISE)

Departmental Report : REP-1998-273

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Report ID:REP-1998-273
Title:Scalable Trigger Processing in TriggerMan
Authors:Eric N. Hanson

Mohan Konyala

Lloyd Noronha

Albert Vernon

Current database trigger systems have extremely limited scalability. Some commercial systems allow only one trigger per table to be defined for each type of update event. Application systems could use the ability to create thousands or even millions of triggers. The advent of the Internet and the World Wide Web has made it even more important that trigger systems scale up since users could create large number of triggers via a web interface. This paper presents a way to develop a truly scalable trigger system. Scalability is achieved with a trigger cache to use main memory effectively, and a memory-conserving selection predicate index based on the use of unique expression formats called expression signatures. A key observation is that if a very large number of triggers are created, most will have the same structure, except for the appearance of different constant values. Expression signatures are used to divide selection predicates of triggers into equivalence classes. When a trigger is created, tuples are added to special relations created for expression signatures if needed. These tables can be augmented with a database index or main-memory index structure to serve as a predicate index.

Supporting Files:file icon (1,252 KB)file icon REP-1998-273.pdf (142 KB)
Posted:December 31, 1997