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HBase >> mail # user >> Short-circuit reads


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David Koch 2013-01-27, 22:29
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Jean-Daniel Cryans 2013-01-27, 22:45
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Ted 2013-01-27, 22:34
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Jean-Marc Spaggiari 2013-01-27, 22:38
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Re: Short-circuit reads
On Sun, Jan 27, 2013 at 2:38 PM, Jean-Marc Spaggiari
<[EMAIL PROTECTED]> wrote:
> Does this have a significant increase on HBase performances?

Ted beats me to linking to my own presentation :P

> And what
> are the "risks" associated with short-circuit activation (if any)? No
> risks of corrupting data?

No, nothing, apart.

>
> Can this be activated after tables are already populated?

Not related at all, this is a region server configuration.

>
> 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
>>
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Jean-Marc Spaggiari 2013-01-27, 22:55
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David Koch 2013-01-27, 23:16
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Jean-Daniel Cryans 2013-01-28, 02:56
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Jean-Marc Spaggiari 2013-01-28, 12:45
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Ted Yu 2013-01-27, 22:45