The results show that, B -tree is more efficient than
Merge-Join since B+
-tree skips many irrelevant ele-
ments. Moreover, the bloom filter only depends on the
minimum IDList with the fewest elements and is es-
sentially independent of the other IDLists having high
frequencies; therefore, it significantly outperforms
B+
-tree and Merge-Join, when one keyword has a low
frequency while others have high frequencies.