What is the difference between Caching and Pooling?

Question

What is the difference between Caching and Pooling?

Answer 1

Cache - store frequently used values, typically because the lookup and/or creation is non-trivial. e.g. if a lookup table from a database is frequently used, or values are read from a file on disk, it's more efficient to keep it in memory and refresh it periodically.

A cache only manages object lifetime in the cache, but does not impose semantics on what is held in the cache. A cache also doesn't create the items, but just stores objects.

Pool - term to describe a group of resources that are managed by the pool itself. e.g. (Database) Connection Pool - When a connection is needed it is obtained from the pool, and when finished with is returned to the pool.

The pool itself handles creation and destruction of the pooled objects, and manages how many objects can be created at any one time.

Pools are typically used to reduce overhead and throttle access to resources. You wouldn't want every servlet request opening a new connection to the database. Because then you have a 1:1 relationship between active requests and open connections. The overhead of creating an destroying these connections is wasteful, plus you could easily overwhelm your database. by using a pool, these open connections can be shared. For example 500 active requests might be sharing as little as 5 database connections, depending on how long a typical request needs the connection.

Cache Pool - mostly seems to describe the number of (independent?) cache's that exist. E.g. an asp.net application has 1 cache per Application Domain (cache isn't shared between asp.net applications). Literally a pool of caches, although this term seems to be used rarely.