Production Settings.yaml.example is not useable as is
The Production context Settings.yaml.example contains the following lines:
dbname: 'quickstart' # adjust to your database name
user: '' # adjust to your database user
password: '' # adjust to your database password
doctrine: # If you have APC, you should consider using it for Production, # also MemcacheCache and XcacheCache exist. # cacheImplementation: 'Doctrine\Common\Cache\ApcCache'
If used as is this will clean the doctrine settings as everything below doctrine is commented out, so an empty value is assigned. This leads to unsuspected errors that are difficult to track down to this.
A safe example should have the doctrine key commented out too.