You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@cassandra.apache.org by "Jonathan Ellis (JIRA)" <ji...@apache.org> on 2011/04/11 17:34:05 UTC
[jira] [Resolved] (CASSANDRA-1825) Separation of Data
(Cached/Non-Cached)
[ https://issues.apache.org/jira/browse/CASSANDRA-1825?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Jonathan Ellis resolved CASSANDRA-1825.
---------------------------------------
Resolution: Later
Fix Version/s: (was: 0.8)
> Separation of Data (Cached/Non-Cached)
> --------------------------------------
>
> Key: CASSANDRA-1825
> URL: https://issues.apache.org/jira/browse/CASSANDRA-1825
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Chris Goffinet
>
> At the moment Cassandra goes through the ROW-READ stage to fetch data from the page cache, and if it's not in the page cache, it goes to disk.
> Data that is currently hot (in page cache) will block if all I/O threads are busy reading from disk. We should seriously look at implementing a buffer pool similar to MySQL for storing data in-memory, and our I/O threads be dedicated to just going to disk. I suggest studying how InnoDB does scheduling as well, they have good lessons to learn from.
> Scaling I/O by thread's isn't going to be a good solution here either. I would argue that going past 64 threads for I/O is just going to hurt overall performance based on context switching.
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira