(data structure)

Definition: Use a short list or array of hash tables to implement a hash table with aging to expire items. To expire items, add a new table at the head of the list and drop the oldest table, along with its contents. To find an item, search all the tables.

Generalization (I am a kind of ...)
hash table.

See also move-to-front heuristic, priority queue.

Note: "The name is a combination of 'hashmap' and 'conveyor belt.'"

This data structure may be used for a least recently used (LRU) cache: move an item to the newest table when it is used. Other policies may be implemented by moving items according to other criteria.

Author: PEB

More information

William Grosso, The Hashbelt Data Structure, O'Reilly, 9 January 2002.

Go to the Dictionary of Algorithms and Data Structures home page.

If you have suggestions, corrections, or comments, please get in touch with Paul Black.

Entry modified 6 May 2019.
HTML page formatted Mon May 6 10:22:33 2019.

Cite this as:
Paul E. Black, "hashbelt", in Dictionary of Algorithms and Data Structures [online], Paul E. Black, ed. 6 May 2019. (accessed TODAY) Available from: