A spec failed with this message:
ActiveRecord::ConnectionTimeoutError:
could not obtain a connection from the pool within 5.000 seconds (waited 5.000 seconds); all pooled connections were in use
The error seems to be raised when trying to authenticate the user
through Devise in a before_action block. Increasing the pool size by one
helped.
I don't know why our app needs more than 5 connections at the same time.
Maybe some gem "forgets" to release connections?
This allows us to tune for UK. The hypothesis from @kristinalim is:
> From what I understand, it can result to Rails processes waiting for
each other to complete, while the DB server can take more simultaneous
connections.
