[
https://issues.apache.org/jira/browse/CASSANDRA-1470?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12970230#action_12970230
]
Jonathan Ellis commented on CASSANDRA-1470:
-------------------------------------------
bq. This article is talking about NOREUSE flag being a no-op but we are using
DONTNEED which does work
Peter wrote a book earlier in the ticket about DONTNEED -- it sounds like it
could work but once you handle all the corner cases it may not actually be
simpler than direct i/o. I'm open to giving it a try, though.
bq. add a method long[] pagesInPageCache() which uses the posix mincore()
function to detect the offsets of pages for this file currently in page cache
bq. use getActiveKeys() to detect which SSTables being compacted are in the os
cache and make sure the subsequent pages in the new compacted SSTable are kept
in the page cache for these keys
Let's avoid growing the scope of this ticket and make a new one for the
"pre-heat sstables post-compaction" feature.
> use direct io for compaction
> ----------------------------
>
> Key: CASSANDRA-1470
> URL: https://issues.apache.org/jira/browse/CASSANDRA-1470
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Jonathan Ellis
> Assignee: Pavel Yaskevich
> Fix For: 0.7.1
>
> Attachments: 1470-v2.txt, 1470.txt, CASSANDRA-1470-for-0.6.patch,
> CASSANDRA-1470-v10-for-0.7.patch, CASSANDRA-1470-v11-for-0.7.patch,
> CASSANDRA-1470-v12-0.7.patch, CASSANDRA-1470-v2.patch,
> CASSANDRA-1470-v3-0.7-with-LastErrorException-support.patch,
> CASSANDRA-1470-v4-for-0.7.patch, CASSANDRA-1470-v5-for-0.7.patch,
> CASSANDRA-1470-v6-for-0.7.patch, CASSANDRA-1470-v7-for-0.7.patch,
> CASSANDRA-1470-v8-for-0.7.patch, CASSANDRA-1470-v9-for-0.7.patch,
> CASSANDRA-1470.patch,
> use.DirectIORandomAccessFile.for.commitlog.against.1022235.patch
>
>
> When compaction scans through a group of sstables, it forces the data in the
> os buffer cache being used for hot reads, which can have a dramatic negative
> effect on performance.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
