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https://issues.apache.org/jira/browse/CASSANDRA-5342?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jonathan Ellis reassigned CASSANDRA-5342:
-----------------------------------------

    Assignee: Marcus Eriksson
    
> ancestors are not cleared in SSTableMetadata after compactions are done and 
> old SSTables are removed
> ----------------------------------------------------------------------------------------------------
>
>                 Key: CASSANDRA-5342
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-5342
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>    Affects Versions: 1.1.3
>            Reporter: Wei Zhu
>            Assignee: Marcus Eriksson
>             Fix For: 1.2.6
>
>         Attachments: Screen Shot 2013-03-13 at 12.05.08 PM.png
>
>
> We are using LCS and have total of 38000 SSTables for one CF. During LCS, 
> there could be over a thousand SSTable involved. All those SSTable IDs are 
> stored in ancestors field of SSTableMetatdata for the new table. In our case, 
> it consumes more than 1G of heap memory for those field. Put it in 
> perspective, the ancestors consume 2 - 3 times more memory than bloomfilter 
> (fp = 0.1 by default) in LCS. 
> We should remove those ancestors from SSTableMetadata after the compaction is 
> finished and the old SSTable is removed. It  might be a big deal for Sized 
> Compaction since there are small number of SSTable involved. But it consumes 
> a lot of memory for LCS. 
> At least, we shouldn't load those ancestors to the memory during startup if 
> the files are removed. 
> I would love to contribute and provide patch. Please let me know how to 
> start. 

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