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From "Marcus Eriksson (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-11350) Max_SSTable_Age isn't really deprecated in DTCS
Date Mon, 14 Mar 2016 19:29:33 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-11350?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15193983#comment-15193983
] 

Marcus Eriksson commented on CASSANDRA-11350:
---------------------------------------------

max_sstable_age_days is left at 1000 years, if someone wants to get the exact behaviour they
had before

With those settings you will do compaction in 1day-sized windows until they are 1 year old.
But the thing is you will actually not do any compaction unless you have to (like after repair
etc) since the windows don't change, so keeping max_sstable_age_days at 1 year is quite pointless.

Problem with max_sstable_age_days is that. If you bootstrap a new node for example you can
end up with a huge amount of sstables older than max_sstable_age_days

> Max_SSTable_Age isn't really deprecated in DTCS
> -----------------------------------------------
>
>                 Key: CASSANDRA-11350
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-11350
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Compaction
>         Environment: PROD
>            Reporter: Anubhav Kale
>            Priority: Minor
>
> Based on the comments in https://issues.apache.org/jira/browse/CASSANDRA-10280, and changes
made to DateTieredCompactionStrategyOptions.java, the Max_SSTable_Age field is marked as deprecated.
> However, this is still used to filter the old SS Tables in DateTieredCompactionStrategy.java.
Once those tables are filtered, Max_Window_Size is used to limit how back in time we can go
(essentially how Max_SSTable_Age was used previously).
> So I am somewhat confused on the exact use of these two fields. Should Max_SSTable_Age
be really removed and Max_Window_Size be used to filter old tables (in which case it should
be set to 1 year as well) ?
> Currently, Max_SSTable_Age = 1 Year, and Max_Window_Size = 1 Day. What is the expected
behavior with these settings ?



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