[jboss-jira] [JBoss JIRA] Commented: (JGRP-1098) NAKACK: retransmitted OOB messages are retransmitted as regular messages

[Bela Ban (JIRA)]

    [ https://jira.jboss.org/jira/browse/JGRP-1098?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12494367#action_12494367 ] 

Bela Ban commented on JGRP-1098:
--------------------------------

We could require that retransmitted multicast messages are *always* retransmitted as a multicast, then we'd not need to copy them !

Or: in sendXmitRsp(), we check whether use_mcast_xmit is true (default) and then simply send a copy of the message down (do we need a copy?), or else wrap the message.

Q: why do we set message.src to local_addr for a wrapping message ?

> NAKACK: retransmitted OOB messages are retransmitted as regular messages
> ------------------------------------------------------------------------
>
>                 Key: JGRP-1098
>                 URL: https://jira.jboss.org/jira/browse/JGRP-1098
>             Project: JGroups
>          Issue Type: Bug
>            Reporter: Bela Ban
>            Assignee: Bela Ban
>             Fix For: 2.8
>
>
> If P sends OOB messages 1-10, and Q only receives 1 and 2, and the later receives P:11, then it'll ask P for retransmission of messages P:3 - P:10. P *wraps* each retransmitted message and sends it as *regular* message to Q. Because regular messages are handled sequentially, by the regular thread pool, each message will be sent up to NAKACK (where it is unwrapped and sent further up) sequentially, destroying the semantics of OOB messages with concurrent and unordered delivery !
> SOLUTION: check whether an original message is OOB and - if so - set the wrapping message as OOB, too.
> TODO: check why we actually wrap retransmitted messages in NAKACk (we don't do it in UNICAST) ! Maybe this is leftover code from the days when retransmitted messages were bundled in NAKACK itself ? We should be able to simply copy the retransmitted message and send it to the requester (or all if mcast_xmit=true).
> TODO: why are we setting the msg.setSrc() in a retransmitted message ?

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