Brief announcement: large-scale multimaps

Michael T. Goodrich, Michael Mitzenmacher

Abstract: Many data structures support dictionaries, also known as maps or associative arrays, which store and manage a set of key-value pairs. A multimap is generalization that allows multiple values to be associated with the same key. We study how multimaps can be implemented efficiently online in external memory frameworks, with constant expected I/O. The key technique used to achieve our results is a combination of cuckoo hashing using buckets that hold multiple items with a multiqueue implementation to cope with varying numbers of values per key.