---
features:
  - |
    Added the config option "oslo_rpc_executor" sets an executor type used by
    Oslo Messaging framework. Defines how Oslo Messaging based RPC subsystem
    processes incoming calls. Allowed values: "eventlet", "threading" and
    "blocking". However, "blocking" is deprecated by the Oslo Messaging team
    and may be removed in the next versions.
    The reason of adding this option was in the issues occuring when using
    MySQLDb database driver and "eventlet" RPC executor. Once in a while,
    the system would hang on a deadlock caused by the fact that the DB
    driver wasn't eventlet-friendly and dispatching of green threads didn't
    work properly. That's why "blocking" was used. Now it's been proven that
    a combination of "eventlet" executor and PyMysql driver works well. The
    configuration option for the RPC executor though allows to rollback to
    "blocking" in case if regression is found, or also experiment with
    "threading".
