== About

This is Nick's connection pool branch, wherein he attempts to rewrite Rails' connection handling code to
be more thread-safe, and to add connection pooling features.

== Goals

- Preserve Rails' lazy connection acquisition and caching strategy behavior as it exists prior to this work.
- Add ability to configure a connection pool to limit the number of connections made to a database in multiple-thread scenarios.
- Threads will block for a configurable timeout if the pool is exhausted until a connection is available.
- If none is available during the timeout period, an exception will be raised.
- Add a checkout/checkin API to reserve and release a connection to/from the pool.
- Add several different connection handling/pooling classes to serve different needs:
  - proper fixed-size connection pool
  - connection-per-thread with no maximum on the number of connections
  - single thread cached connection
  - pass-through to external connection pool (JRuby/JNDI data source connection pool)

== TODO

Remaining tasks:

- Review and put the thing to real work.
- Look at whether existing clear_* or verify_* methods can be deprecated or removed.