module for LRU cache in memory

 The module Tie::Cache module implements a least recently used (LRU) cache in
 memory through a tie interface. Any time data is stored in the tied hash,
 that key/value pair has an entry time associated with it, and as the cache
 fills up, those members of the cache that are the oldest are removed to make
 room for new entries.
 .
 So, the cache only "remembers" the last written entries, up to the size
 of the cache. This can be especially useful if you access great amounts
 of data, but only access a minority of the data a majority of the time.