Chris Jones has written up another post about a feature in some of the latest OCI8 libraries for PHP - result caching.
Oracle Database 11g introduced "server-side"and "client-side" result caches. The database cache is enabled with the RESULT_CACHE_MODE database parameter, which has several modes. With the default mode, queries for which you want results to be cached need a hint added - No PHP changes are required.
This caching is perfect for results from smaller lookup tables and can drop CPU usage by quite a bit. Oracle automatically takes care of validating the cache entries when something changes the stored results so your query is always fetching the latest (without having to worry about a timestamp on the cache or anything like that). He gives a few examples of how it would work, comparing the queries both with and without the caching.