emqx4.3/examples/slow_subs.conf.example

##--------------------------------------------------------------------
## Slow Subscribers Statistics
##
## Count subscribers with topics whose transfer time exceeds the threshold
##--------------------------------------------------------------------
## Note: This is an example of how to configure this feature
##       you should copy and paste the below data into the emqx.conf for working

slow_subs {
    ## Stats Threshold
    threshold = 500ms

    ## Expire time of the record which in Top-K record
    expire_interval = 300ms

    ## Maximum number of Top-K record
    top_k_num = 10

    ## Stats Type
    ## Value:
    ## - whole: from the time the message arrives at EMQX until the message transmission completes
    ## - internal: from when the message arrives at EMQX until when EMQX starts delivering the message
    ## - response: from the time EMQX starts delivering the message until the message transmission completes
    stats_type = whole

    ## use true to enable this
    enable = false
}