##--------------------------------------------------------------------
## EMQX Retainer
##--------------------------------------------------------------------

## Where to store the retained messages.
##
## Notice that all nodes in the same cluster have to be configured to
retainer {
  ## enable/disable emqx_retainer
  enable = true

  ## Periodic interval for cleaning up expired messages. Never clear if the value is 0.
  ##
  ## Value: Duration
  ##  - h: hour
  ##  - m: minute
  ##  - s: second
  ##
  ## Examples:
  ##  - 2h:  2 hours
  ##  - 30m: 30 minutes
  ##  - 20s: 20 seconds
  ##
  ## Default: 0s
  msg_clear_interval = 0s

  ## Message retention time. 0 means message will never be expired.
  ##
  ## Default: 0s
  msg_expiry_interval = 0s

  ## When the retained flag of the PUBLISH message is set and Payload is empty,
  ## whether to continue to publish the message.
  ## see: http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718038
  ##
  ## Default: false
  #stop_publish_clear_msg = false

  ## The message read and deliver flow rate control
  ## When a client subscribe to a wildcard topic, may many retained messages will be loaded.
  ## If you don't want these data loaded to the memory all at once, you can use this to control.
  ## The processing flow:
  ##   load batch_read_number retained message from storage ->
  ##    deliver ->
  ##    repeat this, until all retianed messages are delivered
  ##
  flow_control {
    ## The messages batch number per read from storage. 0 means no limit
    ##
    ## Default: 0
    batch_read_number = 0

    ## The number of retained message can be delivered per batch
    ## Range: [0, 1000]
    ## Note: If this value is too large, it may cause difficulty in applying for the token of deliver
    ##
    ## Default: 0
    batch_deliver_number = 0

    ## The rate limiter name for retained messages delivery.
    ## In order to avoid delivering too many messages to the client at once,  which may cause the client
    ## to block or crash, or message dropped due to exceeding the size of the message queue. We need
    ## to specify a rate limiter for the retained messages delivery to the client.
    ##
    ## The names of the available rate limiters are taken from the existing rate limiters under `limiter.batch`.
    ## You can remove this field if you don't want any limit
    ## Default: retainer
    batch_deliver_limiter = retainer
  }

  ## Maximum retained message size.
  ##
  ## Value: Bytes
  max_payload_size = 1MB

  ## Storage backend parameters
  ##
  ## Value: built_in_database
  ##
  backend {

    type = built_in_database

    ## storage_type: ram | disc
    storage_type = ram

    ## Maximum number of retained messages. 0 means no limit.
    ##
    ## Value: Number >= 0
    max_retained_messages = 0
    }
}