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https://issues.apache.org/jira/browse/FLINK-21373?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ASF GitHub Bot updated FLINK-21373:
-----------------------------------
    Labels: auto-unassigned pull-request-available  (was: auto-unassigned)

> Port RabbitMQ Sink to FLIP-143 API
> ----------------------------------
>
>                 Key: FLINK-21373
>                 URL: https://issues.apache.org/jira/browse/FLINK-21373
>             Project: Flink
>          Issue Type: Improvement
>          Components: Connectors/ RabbitMQ
>            Reporter: Jan Westphal
>            Priority: Minor
>              Labels: auto-unassigned, pull-request-available
>             Fix For: 1.12.0
>
>
> *Structure*
> The unified Sink API provides a Writer, a Committer and a GlobalCommitter. 
> Right now we don’t see the need to use the Committer and GlobalCommitter as 
> the Writer is sufficient to hold up to the consistencies. Since we are in the 
> need of asynchronous RabbitMQ callbacks to know whether or not a message was 
> published successfully and have to store unacknowledged messages in the 
> checkpoint, there would be a large bidirectional communication and state 
> exchange overhead between the Writer and the Committer.
> *At-most-once*
> The Writer receives a message from Flink and simply publishes it to RabbitMQ. 
> The current RabbitMQ Sink only provides this mode.
> *At-least-once*
> The objective here is, to receive an acknowledgement by RabbitMQ for 
> published messages. Therefore, before publishing a message, we store the 
> message in a Map with the sequence number as its key. If the message is 
> acknowledged by RabbitMQ we can remove it from the Map. If we don’t receive 
> an acknowledgement for a certain amount of time (or a RabbitMQ specific so 
> called negative acknowledgement)  we will try to resend the message when 
> doing a checkpoint.
> *Exactly-once*
> On checkpointing we send all messages by Flink in transaction mode to 
> RabbitMQ. This way, all the messages get sent or are rolled back on failure. 
> All messages that are not sent successfully are written to the checkpoint and 
> are tried to be sent with the next checkpoint.



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