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Posted to commits@cassandra.apache.org by "Marcus Eriksson (JIRA)" <ji...@apache.org> on 2015/09/07 19:11:47 UTC

[jira] [Updated] (CASSANDRA-10280) Make DTCS work well with old data

     [ https://issues.apache.org/jira/browse/CASSANDRA-10280?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Marcus Eriksson updated CASSANDRA-10280:
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    Description: 
Operational tasks become incredibly expensive if you keep around a long timespan of data with DTCS - with default settings and 1 year of data, the oldest window covers about 180 days. Bootstrapping a node with vnodes with this data layout will force cassandra to compact very many sstables in this window.

We should probably put a cap on how big the biggest windows can get. We could probably default this to something sane based on max_sstable_age (ie, say we can reasonably handle 1000 sstables per node, then we can calculate how big the windows should be to allow that)

  was:
Operational tasks become incredibly expensive if you keep around a long timespan of data with DTCS - with default settings and 1 year of data, the oldest window covers about 180 days. Bootstrapping a node with vnodes with this data layout will force cassandra to compact very many sstables in this window.

We should probably put a cap on how big the biggest windows can get. We could probably default this to something sane based on max_sstable_age (ie, say we can reasonably handle 1000 sstables per node, then we can make calculate how big the windows should be to allow that)


> Make DTCS work well with old data
> ---------------------------------
>
>                 Key: CASSANDRA-10280
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-10280
>             Project: Cassandra
>          Issue Type: Sub-task
>          Components: Core
>            Reporter: Marcus Eriksson
>            Assignee: Marcus Eriksson
>             Fix For: 3.x, 2.1.x, 2.2.x
>
>
> Operational tasks become incredibly expensive if you keep around a long timespan of data with DTCS - with default settings and 1 year of data, the oldest window covers about 180 days. Bootstrapping a node with vnodes with this data layout will force cassandra to compact very many sstables in this window.
> We should probably put a cap on how big the biggest windows can get. We could probably default this to something sane based on max_sstable_age (ie, say we can reasonably handle 1000 sstables per node, then we can calculate how big the windows should be to allow that)



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