[ 
https://issues.apache.org/jira/browse/CASSANDRA-6809?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14365867#comment-14365867
 ] 

Ariel Weisberg commented on CASSANDRA-6809:
-------------------------------------------

I think what Benedict is describing where we only deallocate if the queue has 
more than one available (and > 3) is good idea. If the knob is set too low it 
might give better behavior at steady state?

I would still be +1 since I think it won't matter once we multi-thread 
compression (and I intend to do that for 3.1).

> Compressed Commit Log
> ---------------------
>
>                 Key: CASSANDRA-6809
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-6809
>             Project: Cassandra
>          Issue Type: Improvement
>            Reporter: Benedict
>            Assignee: Branimir Lambov
>            Priority: Minor
>              Labels: docs-impacting, performance
>             Fix For: 3.0
>
>         Attachments: ComitLogStress.java, logtest.txt
>
>
> It seems an unnecessary oversight that we don't compress the commit log. 
> Doing so should improve throughput, but some care will need to be taken to 
> ensure we use as much of a segment as possible. I propose decoupling the 
> writing of the records from the segments. Basically write into a (queue of) 
> DirectByteBuffer, and have the sync thread compress, say, ~64K chunks every X 
> MB written to the CL (where X is ordinarily CLS size), and then pack as many 
> of the compressed chunks into a CLS as possible.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Reply via email to