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https://issues.apache.org/jira/browse/CASSANDRA-5569?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jonathan Ellis updated CASSANDRA-5569:
--------------------------------------

             Reviewer: jbellis
             Priority: Minor  (was: Major)
    Affects Version/s:     (was: 1.2.4)
                       1.2.0
        Fix Version/s:     (was: 1.2.4)
                       1.2.5
               Labels: streaming  (was: )
    
> Every stream operation requires checking indexes in every SSTable
> -----------------------------------------------------------------
>
>                 Key: CASSANDRA-5569
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-5569
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>    Affects Versions: 1.2.0
>            Reporter: Rick Branson
>            Assignee: Rick Branson
>            Priority: Minor
>              Labels: streaming
>             Fix For: 1.2.5
>
>         Attachments: 5569.txt
>
>
> It looks like there's a streaming performance issue when leveled compaction 
> and vnodes get together. To get the candidate set of chunks to stream, the 
> streaming system gets references to every SSTable for a CF. This is probably 
> a perfectly reasonable assumption for non-vnode cases, because the data being 
> streamed is likely distributed across the full SSTable set. This is also 
> probably a perfectly reasonable assumption for size-tiered compaction, 
> because the data is, again, likely distributed across the full SSTable set. 
> However, for each vnode repair performed on LCS CF's, this scan across 
> potentially tens of thousands of SSTables is wasteful considering that only a 
> small percentage of them will actually have data for a given range.
> This manifested itself as "hanging" repair operations with tasks backing up 
> on the MiscStage thread pool.
> The attached patch changes the streaming code so that for a given range, only 
> SSTables for the requested range are checked to be included in streaming.

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