[jira] [Commented] (CASSANDRA-12570) high reads on system_auth

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

    [ https://issues.apache.org/jira/browse/CASSANDRA-12570?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15449402#comment-15449402 ] 

Sam Tunnicliffe commented on CASSANDRA-12570:
---------------------------------------------

For authentication only (i.e. not authorization), system_auth tables are read only when a new client connection is opened. So this suggests that your clients are not using long lived connections, which is rather inefficient (in both this and the general case.)  

When logging in as the default superuser (i.e. "cassandra") reads from system_auth are performed at QUORUM, whereas for any other user (including other superusers) this is done at LOCAL_ONE, which is obviously cheaper.

> high reads on system_auth
> -------------------------
>
>                 Key: CASSANDRA-12570
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-12570
>             Project: Cassandra
>          Issue Type: Bug
>         Environment: Cluster of 5 nodes, 2.1.15
>            Reporter: Etienne Adam
>
> Since we activated authentication on our production cluster today, we're seeing high reads on keyspace "system_auth", which is causing a non negligeable increase in system load.
> - Reads on system_auth are between 7K to 15K/minutes depending on the node.
> - RF for system_auth was set to 5, we changed it to 3 without any visible effect.
> - System loads went from ~1 to ~8
> - Nothing special on the logs (
> We did not find any configuration to fix this, and it seems that authentication alone should not cause that kind of a load.. ?
> Is there more information we can provide to help debug this before we turn off authentication ?



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