
Chapter 12: Performance Evaluation of Logic Programs 509
for instance, the fact that Semi-Naive performs as well as any other strategy
when computing the entire transitive closure of a relation (Bancilhon [1986]).
Further, our data contains no cycles or shortcuts. This is an important limita-
tion since it favors some of the specialized strategies. For instance, there are
cases where Counting performs worse than Magic Sets (Bancilhon et al.
[1986a]). This is not shown by our results since these cases involve shortcuts
in the data.
Acknowledgments
We thank the anonymous referees for numerous comments which improved the
technical content and presentatio ...