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HBase, mail # user - Short-circuit reads


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Re: Short-circuit reads
Jean-Marc Spaggiari 2013-01-27, 22:38
Does this have a significant increase on HBase performances? And what
are the "risks" associated with short-circuit activation (if any)? No
risks of corrupting data?

Can this be activated after tables are already populated?

JM

2013/1/27, Ted <[EMAIL PROTECTED]>:
> For hbase internal checksum, it is not in hbase 0.92.x release.
>
> Please use 0.94.2 or newer release.
>
> Thanks
>
> On Jan 27, 2013, at 2:29 PM, David Koch <[EMAIL PROTECTED]> wrote:
>
>> Hello,
>>
>> I read about "short circuit reads" in the HBase documentation's
>> performance
>> section[1] and was wondering what people's experiences were using this in
>> a
>> production setting.
>>
>> Also,
>>
>> 1. Since only one dedicated user can take advantage of the feature do you
>> launch all jobs as this user?
>> 2. Can dfs.client.read.shortcircuit be set to false for jobs wich are not
>> launched by the short-circuit user in order to avoid exceptions? In other
>> words - can this setting be overriden by the client configuration's
>> hbase-site.xml?
>> 3. In the same context, it is suggested to enable HBase internal
>> checksums[2]. Is this a feature which can be enabled in HBase 0.92.1
>> which
>> is part of the Cloudera 4.1.x release?
>>
>> Thank you,
>>
>> /David
>>
>> [1] http://hbase.apache.org/book/perf.hdfs.html#ftn.d2145e7370
>> [2] https://issues.apache.org/jira/browse/HBASE-5074
>