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From Sanjay Subramanian <Sanjay.Subraman...@wizecommerce.com>
Subject Re: Now give .gz file as input to the MAP
Date Wed, 12 Jun 2013 17:43:16 GMT
Rahul-da

I found bz2 pretty slow (although splittable) so I switched to snappy (only sequence files
are splittable but compress-decompress is fast)

Thanks
Sanjay

From: Rahul Bhattacharjee <rahul.rec.dgp@gmail.com<mailto:rahul.rec.dgp@gmail.com>>
Reply-To: "user@hadoop.apache.org<mailto:user@hadoop.apache.org>" <user@hadoop.apache.org<mailto:user@hadoop.apache.org>>
Date: Tuesday, June 11, 2013 9:53 PM
To: "user@hadoop.apache.org<mailto:user@hadoop.apache.org>" <user@hadoop.apache.org<mailto:user@hadoop.apache.org>>
Subject: Re: Now give .gz file as input to the MAP

Nothing special is required for process .gz files using MR. however , as Sanjay mentioned
, verify the codec's configured in core-site and another thing to note is that these files
are not splittable.

You might want to use bz2 , these are splittable.

Thanks,
Rahul


On Wed, Jun 12, 2013 at 10:14 AM, Sanjay Subramanian <Sanjay.Subramanian@wizecommerce.com<mailto:Sanjay.Subramanian@wizecommerce.com>>
wrote:

hadoopConf.set("mapreduce.job.inputformat.class", "com.wizecommerce.utils.mapred.TextInputFormat");

hadoopConf.set("mapreduce.job.outputformat.class", "com.wizecommerce.utils.mapred.TextOutputFormat");

No special settings required for reading Gzip except these above

I u want to output Gzip


hadoopConf.set("mapreduce.output.fileoutputformat.compress", "true");

hadoopConf.set("mapreduce.output.fileoutputformat.compress.codec", "org.apache.hadoop.io.compress.GzipCodec");


Make sure Gzip codec is defined in core-site.xml
<!-- core-site.xml -->
<property>
    <name>io.compression.codecs</name>
    <value>org.apache.hadoop.io.compress.GzipCodec,org.apache.hadoop.io.compress.DefaultCodec</value>
</property>

I have a question

Why are u using GZIP as input to Map ? These are not splittableā€¦Unless u have to read multilines
(like lines between a BEGIN and END block in a log file) and send it as one record to the
mapper

Also in Non-splitable Snappy Codec is better

Good Luck


sanjay

From: samir das mohapatra <samir.helpdoc@gmail.com<mailto:samir.helpdoc@gmail.com>>
Reply-To: "user@hadoop.apache.org<mailto:user@hadoop.apache.org>" <user@hadoop.apache.org<mailto:user@hadoop.apache.org>>
Date: Tuesday, June 11, 2013 9:07 PM
To: "cdh-user@cloudera.com<mailto:cdh-user@cloudera.com>" <cdh-user@cloudera.com<mailto:cdh-user@cloudera.com>>,
"user@hadoop.apache.org<mailto:user@hadoop.apache.org>" <user@hadoop.apache.org<mailto:user@hadoop.apache.org>>,
"user-help@hadoop.apache.org<mailto:user-help@hadoop.apache.org>" <user-help@hadoop.apache.org<mailto:user-help@hadoop.apache.org>>
Subject: Now give .gz file as input to the MAP

Hi All,
    Did any one worked on, how to pass the .gz file as  file input for mapreduce job ?

Regards,
samir.

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