Program monitoring and measuring is the activity of collecting information about the execution characteristics of a program. Although this activity is occasionally supported by special-purpose hardware, it is normally done by adding instrumentation code to the program so that it collects interesting data as it runs. Unfortunately, this alteration is itself a difficult task involving all the complexities of programming. Given some questions to be answered, the programmer must determine what data must be collected, determine where in the program those data can be collected, and add code to the program to collect that data and to process it to produce the desired results. The goal of the work described is to automate the process. A high-level program monitoring and measuring system is presented. The system provides a high-level specification language to let programmers specify what they want to know about their program's execution. It automatically generates an augmented program whose execution produces both the results of the original program and answers to the specified questions.>

This paper presents a language for specifying database updates, queries and rule triggers, and describes how triggers can be compiled into an efficient mechanism. The rule language allows specification of both state and transition constraints as special cases, but is more general than either. The implementation we describe compiles rules and updates independently of each other. Thus rules can be added or deleted without recompiling any update program and vice versa.