  Grover's quantum search algorithm is considered as one of the milestone in
the field of quantum computing. The algorithm can search for a single match in
a database with $N$ records in $O(\sqrt{N})$ assuming that the item must exist
in the database with quadratic speedup over the best known classical algorithm.
This review paper discusses the performance of Grover's algorithm in case of
multiple matches where the problem is expected to be easier. Unfortunately, we
will find that the algorithm will fail for $M>3N/4$, where $M$ is the number of
matches in the list.
