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Hadoop >> mail # user >> Re: Is the input values for reduce method sorted in any order?


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Re: Is the input values for reduce method sorted in any order?
Harsh, thanks.

On Tue, Mar 26, 2013 at 2:28 PM, Harsh J <[EMAIL PROTECTED]> wrote:
> MR will partition and sort inputs by keys by the key comparator, and
> then group them together when reading back via a grouping comparator
> (which is usually the same as the key comparator). It will not re-sort
> the values nor look at any of the value's fields during this process.
>
> If you want your values to be sorted, implementing secondary sort
> would need to happen wherein you extract the value-sort attributes
> onto your keys and have them grouped differently.
>
> On Tue, Mar 26, 2013 at 10:55 AM, jingguo yao <[EMAIL PROTECTED]> wrote:
>> Is the Iterable values associated with a key sorted in any order?  Are
>> there are any configuration options controlling how the input values are
>> sorted?
>>
>> I know that the secondary sort way can be used to achieve the same
>> effect. I am not asking for a workaround.
>>
>> --
>> Jingguo
>
>
>
> --
> Harsh J

--
Jingguo
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB