The major bottleneck in the apriori algorithm is the generation of candidate rules in Phase 1—for example, = {item 1 , item 2 , . . . , item m } can produce 2m possible itemsets. Because of its multiphase design, it first generates these itemsets and then works toward finding the frequent itemsets. This limitation is a huge performance bottleneck and makes the apriori algorithm unsuitable for larger items.