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https://issues.apache.org/jira/browse/CASSANDRA-6890?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13984870#comment-13984870
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Joshua McKenzie commented on CASSANDRA-6890:
--------------------------------------------

nio2 and FILE_SHARE_DELETE still won't allow us to delete hard-links to 
memory-mapped files - 
[reference|http://www.osronline.com/showThread.cfm?link=64732].  While that 
link refers to files in general, I tested with nio2 and confirmed it applies to 
memory-mapped hard-links on Windows as well.

I'll retest perf w/both mixed and cql native; I went in with the expectation 
that stress defaulted to cql3 at this point given the development focus.  
@Pavel - I'll get the perf record results after re-testing on Windows.


> Standardize on a single read path
> ---------------------------------
>
>                 Key: CASSANDRA-6890
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-6890
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>            Reporter: Joshua McKenzie
>            Assignee: Joshua McKenzie
>              Labels: performance
>             Fix For: 3.0
>
>         Attachments: mmap_gc.jpg, mmap_jstat.txt, mmap_perf.txt, 
> nommap_gc.jpg, nommap_jstat.txt
>
>
> Since we actively unmap unreferenced SSTR's and also copy data out of those 
> readers on the read path, the current memory mapped i/o is a lot of 
> complexity for very little payoff.  Clean out the mmapp'ed i/o on the read 
> path.



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