[jboss-jira] [JBoss JIRA] (JGRP-1743) NAKACK*: log a warning if xmit_table gets large

[Dennis Reed (JIRA)]

    [ https://issues.jboss.org/browse/JGRP-1743?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12924099#comment-12924099 ] 

Dennis Reed commented on JGRP-1743:
-----------------------------------

I see this as just an alert that something is going horribly wrong, so it wouldn't have to be particularly accurate.

If there are a million messages in the table, or using GB's of memory, something is definitely wrong.
But the threshold could probably be set quite a bit lower than that.  Maybe test what a "normal" size is during some of our load tests,
and set it two or three times as high, but configurable just in case an application expects to have a lot of messages in NAKACK for some reason?

Size of the table would probably be better, but if it's expensive to calculate then number of messages could be used.

It definitely shouldn't be checked too often to affect performance
                
> NAKACK*: log a warning if xmit_table gets large
> -----------------------------------------------
>
>                 Key: JGRP-1743
>                 URL: https://issues.jboss.org/browse/JGRP-1743
>             Project: JGroups
>          Issue Type: Feature Request
>    Affects Versions: 3.4.1
>            Reporter: Dennis Reed
>            Assignee: Bela Ban
>            Priority: Minor
>             Fix For: 3.5
>
>
> There have been some cases where NAKACK* accumulates large number of messages, causing OutOfMemoryErrors.
> Large numbers of messages in NAKACK* would almost always indicate a problem, which the user should be aware of.
> Logging a warning if the number of messages in NAKACK passes a configurable threshold would let the user investigate and take action sooner before a catastrophic OutOfMemoryError, or other issues occur.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira