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vernemq / vernemq

A distributed MQTT message broker based on Erlang/OTP. Built for high quality & Industrial use cases. The VerneMQ mission is active & the project maintained. Thank you for your support!
https://vernemq.com
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Data loss observed from ernemq to clients where clients doesn't have a clientID but uses the same username and password #1606

Closed onrao closed 5 months ago

onrao commented 4 years ago

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Environment

Expected behaviour

There shouldn't be a dataloss

Actual behaviour

Dataloss observed

onrao commented 4 years ago

Clients are using the shared subscription

ioolkos commented 4 years ago

@onrao could you be even more specific? what is data loss? how do you determine that? how many shared subscribers, with what shared subscriber policy? have you tested with providing a ClientID vs no ClientID?

onrao commented 4 years ago

Hi ioolkos

Thank you for the reply, We would like to understand the behaviour of verneMQ when

  1. There is no clientID in Connect request and client provides only registered username,password, keepalive session as 0, connect timeout as 60601000

2.We had this client application from 3rd party which is enabling the Shared subscription with policiy on topic filter "$shared/json//+/+/attrs"

When such two instances of the same client aplication is running Ideally because of the shared subscription by the clients ,VerneMQ should distribute based on the clients connected and session active conditions , Here we are seeing thedistribution of the subscribed topics properly inbetween we are loosing some published topics (10 to 20%)which are under this shared subscription topics.

Please find the docker configuration of VerneMQ is used

DOCKER_VERNEMQ_ACCEPT_EULA yes DOCKER_VERNEMQ_ALLOW_ANONYMOUS off DOCKER_VERNEMQ_listener.tcp.LISTENER.proxy_protocol on DOCKER_VERNEMQ_listener.tcp.proxy_protocol_use_cn_as_username on DOCKER_VERNEMQ_LOGCONSOLE off DOCKER_VERNEMQ_LOGCONSOLE__LEVEL debug DOCKER_VERNEMQ_MAX_INFLIGHT_MESSAGES 0 DOCKER_VERNEMQ_MAX_OFFLINE_MESSAGES -1 DOCKER_VERNEMQ_MAX_ONLINE_MESSAGES -1 DOCKER_VERNEMQ_persistent_client_expiration never DOCKER_VERNEMQ_plugins.vmq_passwd on DOCKER_VERNEMQ_USER_client1 client1 DOCKER_VERNEMQ_USER_client client DOCKER_VERNEMQ_OUTGOING_CLUSTERING_BUFFER_SIZE 100000

ioolkos commented 5 months ago

Closing this. For future readers: VerneMQ will assign a random ClientID for MQTT clients that connect without giving a ClientID. This is not suitable for shared subscriptions (and persistent sessions), which need stable ClientIDs.

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