cassandra-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "T Jake Luciani (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-1902) Migrate cached pages during compaction
Date Thu, 31 Mar 2011 15:06:06 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-1902?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13013996#comment-13013996
] 

T Jake Luciani commented on CASSANDRA-1902:
-------------------------------------------

Here's my test results:

1. Loaded in just enough to fit in page cache + flushed
2. Primed reads
3. Overwrite with same data + flushed
4. Ran major compaction while reading as much as possible the entire time.

Read results for 100k during major compaction (migration ON):
{noformat}
19,13,14,14,82,16,15,67,19,14,47,53,74,15,14,46,32,15,13,65,15,14,67,16,13,59,12,11,11
             ^        ^        ^  ^  ^        ^           ^        ^        ^
{noformat}
vs with migration OFF

~14-16 X times, then 260, 68, 16....






> Migrate cached pages during compaction 
> ---------------------------------------
>
>                 Key: CASSANDRA-1902
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-1902
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>    Affects Versions: 0.7.1
>            Reporter: T Jake Luciani
>            Assignee: Pavel Yaskevich
>             Fix For: 0.7.5, 0.8
>
>         Attachments: 0001-CASSANDRA-1902-cache-migration-impl-with-config-option.txt,
1902-BufferedSegmentedFile-logandsleep.txt, 1902-formatted.txt, 1902-per-column-migration-rebase2.txt,
1902-per-column-migration.txt, CASSANDRA-1902-v3.patch, CASSANDRA-1902-v4.patch, CASSANDRA-1902-v5.patch,
CASSANDRA-1902-v6.patch
>
>   Original Estimate: 32h
>          Time Spent: 56h
>  Remaining Estimate: 0h
>
> Post CASSANDRA-1470 there is an opportunity to migrate cached pages from a pre-compacted
CF during the compaction process.  This is now important since CASSANDRA-1470 caches effectively
nothing.  
> For example an active CF being compacted hurts reads since nothing is cached in the new
SSTable. 
> The purpose of this ticket then is to make sure SOME data is cached from active CFs.
This can be done my monitoring which Old SSTables are in the page cache and caching active
rows in the New SStable.
> A simpler yet similar approach is described here: http://insights.oetiker.ch/linux/fadvise/

--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira

Mime
View raw message