[jira] [Updated] (CASSANDRA-4310) Multiple independent Level Compactions in Parallel

["Jonathan Ellis (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CASSANDRA-4310?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Jonathan Ellis updated CASSANDRA-4310:
--------------------------------------

    Affects Version/s:     (was: 1.1.2)
                           (was: 1.1.1)
                       1.0.0
        Fix Version/s: 1.2
             Assignee: Yuki Morishita
              Summary: Multiple independent Level Compactions in Parallel  (was: Multiple independent Level Compactions in Parallel(Useful for SSD). )
    
> Multiple independent Level Compactions in Parallel
> --------------------------------------------------
>
>                 Key: CASSANDRA-4310
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-4310
>             Project: Cassandra
>          Issue Type: New Feature
>          Components: Core
>    Affects Versions: 1.0.0
>            Reporter: sankalp kohli
>            Assignee: Yuki Morishita
>              Labels: compaction, features, leveled, performance, ssd
>             Fix For: 1.2
>
>
> Problem: If you are inserting data into cassandra and level compaction cannot catchup, you will create lot of files in L0.  
> Here is a solution which will help here and also increase the performance of level compaction.
> We can do many compactions in parallel for unrelated data.
> 1) For no over lapping levels. Ex: when L0 stable is compacting with L1, we can do compactions in other levels like L2 and L3 if they are eligible.
> 2) We can also do compactions with files in L1 which are not participating in L0 compactions.
> This is specially useful if you are using SSD and is not bottlenecked by IO. 
> I am seeing this issue in my cluster. The compactions pending are more than 50k and the disk usage is not that much(I am using SSD).
> I am doing multithreaded to true and also not throttling the IO by putting the value as 0. 
>  

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