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https://issues.apache.org/jira/browse/ACCUMULO-550?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Adam Fuchs updated ACCUMULO-550:
--------------------------------

    Summary: Collocate rfile index entries within file  (was: Colocate rfile 
index entries within file)
    
> Collocate rfile index entries within file
> -----------------------------------------
>
>                 Key: ACCUMULO-550
>                 URL: https://issues.apache.org/jira/browse/ACCUMULO-550
>             Project: Accumulo
>          Issue Type: Improvement
>          Components: tserver
>            Reporter: Keith Turner
>            Assignee: Keith Turner
>             Fix For: 1.5.0, 1.4.1
>
>
> Before multi-level indexes were introduced, when an an rfile was written its 
> entire index was held in memory and written out then the file was closed.  
> With the introduction of multilevel index each index block is written when it 
> fills up as the file is being written.  This was done to handle the case 
> where the index may not fit into memory.  This leads to index blocks being 
> sprinkled through the file.   So any operation that iterates over the entire 
> index can be slow because it turns into a lot of random accesses.   
> One possible solution is to buffer lots of index blocks up to some some 
> threshold and write out alot of index blocks at once.  This would make a scan 
> of the index much faster as it would turn into a set of sequential reads of 
> large chunks of data.
> Could buffer all block at a particular level and write them out when the 
> parent index block fills up.

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