rails/rails — pull request #14938 by thedarkone (2014-05-02 08:06:47+00:00)
Title: Reducing AR::ConPool's critical (synchronized) section

This is an alternative (much lighter in scope) PR to #14926, only the smallest possible amount of code is changed.

The objective is to:
* move connection verification outside of `synchronized` section -> 6b3c4f6
* move connection establishment outside of the `synchronized` section -> c6654b1

This should allow for more concurrency. Related: #14891, #14919.