[
https://issues.apache.org/jira/browse/CASSANDRA-2459?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13018837#comment-13018837
]
Pavel Yaskevich commented on CASSANDRA-2459:
--------------------------------------------
Using different sources creates additional I/O pressure where page cache for
the same file should be preserved for mmaping and normal I/O, it seems to me
that making it a single source with parallel compaction mechanism from
CASSANDRA-2191 will lower affect on the live reads during compaction (also
CASSANDRA-1902 with migration enabled can guarantee that page cache will be
preserved were needed).
> move SSTableScanner to use SSTableReader.dfile instead of BRAF
> --------------------------------------------------------------
>
> Key: CASSANDRA-2459
> URL: https://issues.apache.org/jira/browse/CASSANDRA-2459
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Pavel Yaskevich
> Assignee: Pavel Yaskevich
> Fix For: 1.0
>
>
> That can give us the following benefits:
> a). don't need to skip a cache because we will be operating on memory mappings
> b). better performance (not copying data between kernel and user buffers as
> effect gained from using memory mapped segments, avoiding time operating on
> the kernel mode (+ time for switching context and read-ahead pressure) which
> BRAF involves)
> c). less impact on the live-reads
> d). less garbage will be created
> e). less file descriptors opened
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
