Old-stats plugin and fifo_listener permissions

[Grant Keller]

Hello,

Currently working on using the old-stats plugin in dovecot version
2.3.10.1. What file permissions are recommended for the old-stats-mail
and old-stats-user sockets? I was seeing a lack of data from the doveadm
oldstats dump command until I adjusted the default config to the
following:

service old-stats {
  fifo_listener old-stats-mail {
    group =
    mode = 0666
    user = root
  }
  fifo_listener old-stats-user {
    group =
    mode = 0666
    user =
  }
}

Not totally clear on which processes need read or write on those so any
advice is appreciated.