[jira] [Comment Edited] (HBASE-5778) Fix HLog compression's incompatibilities

["Andrew Purtell (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-5778?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13536655#comment-13536655 ] 

Andrew Purtell edited comment on HBASE-5778 at 12/20/12 1:05 AM:
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I've found I need to add -Djava.net.preferIPv4Stack=true on the Maven command line if running tests individually with 'mvn test -Dtest=foo'. Maybe that's it? 

Furthermore, with recent Hadoop 1.0.x or 1.1.x no test that requires the HDFS minicluster will start up without this on my Ubuntu 12 laptop. It looks to me like a rat hole of increasing depth.

Edit: Wrong species of problem :-)
                
      was (Author: apurtell):
    I've found I need to add -Djava.net.preferIPv4Stack=true on the Maven command line if running tests individually with 'mvn test -Dtest=foo'. Maybe that's it? 

Furthermore, with recent Hadoop 1.0.x or 1.1.x no test that requires the HDFS minicluster will start up without this on my Ubuntu 12 laptop. It looks to me like a rabbit hole of increasing depth.
                  
> Fix HLog compression's incompatibilities
> ----------------------------------------
>
>                 Key: HBASE-5778
>                 URL: https://issues.apache.org/jira/browse/HBASE-5778
>             Project: HBase
>          Issue Type: Improvement
>            Reporter: Jean-Daniel Cryans
>            Assignee: Jean-Daniel Cryans
>            Priority: Blocker
>             Fix For: 0.96.0, 0.94.4
>
>         Attachments: 5778.addendum, 5778-addendum.txt, HBASE-5778-0.94.patch, HBASE-5778-0.94-v2.patch, HBASE-5778-0.94-v3.patch, HBASE-5778-0.94-v4.patch, HBASE-5778-0.94-v5.patch, HBASE-5778-0.94-v6.patch, HBASE-5778-0.94-v7.patch, HBASE-5778.patch, HBASE-5778-trunk-v6.patch, HBASE-5778-trunk-v7.patch
>
>
> I ran some tests to verify if WAL compression should be turned on by default.
> For a use case where it's not very useful (values two order of magnitude bigger than the keys), the insert time wasn't different and the CPU usage 15% higher (150% CPU usage VS 130% when not compressing the WAL).
> When values are smaller than the keys, I saw a 38% improvement for the insert run time and CPU usage was 33% higher (600% CPU usage VS 450%). I'm not sure WAL compression accounts for all the additional CPU usage, it might just be that we're able to insert faster and we spend more time in the MemStore per second (because our MemStores are bad when they contain tens of thousands of values).
> Those are two extremes, but it shows that for the price of some CPU we can save a lot. My machines have 2 quads with HT, so I still had a lot of idle CPUs.

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