[
https://issues.apache.org/jira/browse/CASSANDRA-6890?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13951479#comment-13951479
]
Jonathan Ellis commented on CASSANDRA-6890:
-------------------------------------------
bq. the option to keep compression off to improve performance seems pretty
compelling
You're right, more so than I thought.
bq. Personally, I am -1 on removing mmapped IO as an option until we have an
in-process uncompressed page cache that mitigates these problems.
I think I'd be okay removing it if we can get to within 10%.
> Remove mmap'ed i/o from read path
> ---------------------------------
>
> Key: CASSANDRA-6890
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6890
> Project: Cassandra
> Issue Type: Improvement
> Reporter: Joshua McKenzie
> Assignee: Joshua McKenzie
> Priority: Minor
> 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.
--
This message was sent by Atlassian JIRA
(v6.2#6252)
