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https://issues.apache.org/jira/browse/CASSANDRA-21539?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18100056#comment-18100056
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Stefan Miklosovic edited comment on CASSANDRA-21539 at 7/29/26 12:16 PM:
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Clients vtable has the primary key as (address, port) where {{address}} is of 
type {{inet}}. That will report IP address without translation. {{hostname}} 
column, in my view, is meant to be DNS-resolved name, not IP, because we will 
end up with two same values.


was (Author: smiklosovic):
Clients vtable as the primary key as (address, port) where {{address}} is of 
type {{inet}}. That will report IP address without translation. {{hostname}} 
column, in my view, is meant to be DNS-resolved name, not IP, because we will 
end up with two same values.

> 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: 7.x
>
>         Attachments: ci_summary.html, result_details.tar.gz
>
>          Time Spent: 10m
>  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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