On the Power of Query-Independent Compilation

Recursive query processing techniques can be classified into three categories: interpretation, query-dependent compilation and query-independent compilation. Query-dependent compilation compiles IDB (Intensional Data Base) programs based on possible query instantiations into query-specific programs, while query-independent compilation compiles IDB programs into query-independent and easily analyzable relational expressions. Previous studies show that linear recursions can be query-independently compiled into highly regular forms. This study analyzes the power of query-independent compilation and shows that (i) query-independent compilation captures more binding information than other methods for irregular linear recursions; (ii) the compilation provides succinct information for selection of efficient query processing methods; and (iii) it facilitates constraint-based processing of complex queries. Finally, query-independent compilation can be applied to more complex recursions as well.