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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 edited comment on CASSANDRA-6890 at 4/29/14 10:02 PM:
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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 rather than hard-links to files, 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.
was (Author: joshuamckenzie):
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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