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https://issues.apache.org/jira/browse/CASSANDRA-19715?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17855749#comment-17855749
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Michael Semb Wever commented on CASSANDRA-19715:
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If it's a table option then it's global, and can't address the problem of all 
nodes compacting at the same time spiking latencies.

If we're offsetting the actual time-window, instead of just delaying the 
compaction once the current time window is complete, it introduces more 
complexities (not that the idea doesn't have value, but curious if offsetting 
time-windows should be something done for reasons other than operational).

> TWCS - Provide a flag to pick a time when compaction happens for the n-1 
> window
> -------------------------------------------------------------------------------
>
>                 Key: CASSANDRA-19715
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-19715
>             Project: Cassandra
>          Issue Type: New Feature
>            Reporter: Venkata Naladala
>            Priority: Normal
>
> Below are the settings for the TWCS. With the settings below, the compaction 
> for the n-1 window happens at around 00:00 UTC on all the nodes in the 
> cluster. This causes a spike in IO utilization on the entire cluster, which 
> in turn increases the read latencies.
> {{{}compaction = { 'class' : 
> 'org.apache.cassandra.db.compaction.TimeWindowCompactionStrategy', 
> 'compaction_window_size' : 1, 'compaction_window_unit' : 'DAYS', 
> 'max_threshold' : 32, 'min_threshold' : 4{}}}}
> Requesting to provide a new option for TWCS where we can specify when the 
> compaction for n-1 window happens. This way, we can provide a custom time 
> instead of the default time(beginning of the new window) so that we can pick 
> low-traffic hours and avoid impacting the customer.



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