[jira] [Commented] (CASSANDRA-9720) half open tcp connections to cassandra cluster nodes cause 100% cpu load

["Benedict (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-9720?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14614276#comment-14614276 ] 

Benedict commented on CASSANDRA-9720:
-------------------------------------

If you could grab a bunch of {{top -Hbn 1}} and {{jstack}} outputs while the node is exhibiting this behaviour, it might help us narrow down candidates.

> half open tcp connections to cassandra cluster nodes cause 100% cpu load
> ------------------------------------------------------------------------
>
>                 Key: CASSANDRA-9720
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-9720
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>            Reporter: Alexander Piavlo
>
> cassandra 2.1.5
> We spotted that few of the nodes in our cluster got sudden cpu 100% spike which never ended. It's not a GC and not increased reads/writes nodes.
> What we saw is that those nodes that have 100% cpu load
> all have some connections (file descriptios) with "can't identify protocol"
> which indicate those must be unprolery handled abrupt connections by cassandra process.
> http://stackoverflow.com/questions/7911840/seeing-too-many-lsof-cant-identify-protocol
> We are pretty sure what triggered this is the spark cassandra connector
> which sudenly started to get stuck in early discovery of cassandra nodes before running any stages
> We had to restart the affected cassandra processes to get the cpu back to normal
> ps. we had similar issues some time ago with earlier version, of 2.1.x cassandra branch, and ended up solving the problerm by upgrading from spark1.2.1 to spark1.3.1 and also upgrading spark datastax connecor accordingly. Now looks like the problem is back with 99.9% same symptoms
> ps2. We have observed previously several java/cassandra unrelated processes (mainly in php-cli) go crazy with cpu then they had "can't identify protocol" symphoms



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