* PL/SQL (cursors): These programmatic structures-such as functions, procedures, and packages-are also cached and therefore require shared pool memory. PL/SQL structures can consume a tremendous amount of shared pool memory.

* Library cache: This is used to locate objects in the shared pool and to ensure their proper relationship is maintained. While the library cache can be represented as a hashing structure (complete with buckets and chains), it is actually much more complicated than this. Efficient and unfettered library cache operations are central to a well-performing Oracle database system.

* Row cache: Commonly called the dictionary cache, tuning of this cache was automated starting in Oracle 7. The row cache caches Oracle's data dictionary rows (not blocks). Objects like sys.tab$, sys.col$, and sys.auth$ are cached within the shared pool's row cache, rather than in the buffer cache. While Oracle must retrieve an entire block to retrieve a single dictionary table row, the result is significant memory savings and a highly efficient cache. In fact, the row cache can be monitored through the v$rowcache view and typically has an extremely high cache hit ratio of around 99%. While DBAs were initially concerned about Oracle removing manual optimization control, Oracle has done a fantastic job at dictionary object cache management.