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https://issues.apache.org/jira/browse/CASSANDRA-21539?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18111213#comment-18111213
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Stefan Miklosovic commented on CASSANDRA-21539:
-----------------------------------------------

[~nivy] could you please prepare the revert patches? I understand this might be 
quite hard pill to swallow, seeing your work being removed like that, but the 
feedback we got here is quite compelling to move to that direction for now. 

> Querying system_views.clients causes a DNS lookup for each unique connected 
> client address
> ------------------------------------------------------------------------------------------
>
>                 Key: CASSANDRA-21539
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-21539
>             Project: Apache Cassandra
>          Issue Type: Bug
>          Components: Feature/Virtual Tables
>            Reporter: Nivy Kani
>            Assignee: Nivy Kani
>            Priority: Normal
>             Fix For: 4.0.22, 4.1.13, 5.0.10, 6.0-alpha3, 7.0
>
>         Attachments: 4.0-ci_summary.html, 4.0-result_details.tar.gz.zip, 
> 5.0-ci_summary.html, 5.0-result_details.tar.gz, 6.0-ci_summary.html, 
> 6.0-result_details.tar.gz, ci_summary-1.html, ci_summary.html, 
> result_details.tar-1.gz, result_details.tar.gz
>
>          Time Spent: 1h 40m
>  Remaining Estimate: 0h
>
> It looks like queries to the system_views.clients table does a DNS lookup for 
> each unique address: 
> https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/db/virtual/ClientsTable.java#L91
>  
> Given Java's internal DNS caches, this is really only potentially slow on the 
> first query, but we should avoid doing DNS lookups here as a workflow that 
> queries this table on each node to collect client information could 
> potentially overwhelm DNS this way.



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