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Avro >> mail # user >> Generating snappy compressed avro files as hadoop map reduce input files


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Re: Generating snappy compressed avro files as hadoop map reduce input files
If you're using hadoop, why not use AvroSequenceFileOutputFormat - this works fine with snappy (block level compression may be best depending on your data)

On Oct 13, 2013, at 10:58 AM, David Ginzburg <[EMAIL PROTECTED]> wrote:

> As mentioned in http://stackoverflow.com/a/15821136 Hadoop's snappy codec just doesn't work with externally generated files.
>
> Can files generated by DataFileWriter  serve as input files for a map reduce job, specially EMR jobs ?
> From: Bertrand Dechoux <[EMAIL PROTECTED]>
> Sent: Sunday, October 13, 2013 6:36 PM
> To: [EMAIL PROTECTED]
> Subject: Re: Generating snappy compressed avro files as hadoop map reduce input files
>  
> I am not sure to understand the relation between your problem and the way the temporary data are stored after the map phase.
>
> However, I guess you are looking for a DataFileWriter and its setCodec function.
> http://avro.apache.org/docs/current/api/java/org/apache/avro/file/DataFileWriter.html#setCodec%28org.apache.avro.file.CodecFactory%29
>
> Regards
>
> Bertrand
>
> PS : A snappy-compressed avro file is not a standard file which has been compressed afterwards but really a specific file containing compressed blocks. This principle is similar to the SequenceFile's. Maybe that's what you mean by different snappy codec?
>
> On Sun, Oct 13, 2013 at 5:16 PM, David Ginzburg <[EMAIL PROTECTED]> wrote:
> Hi,
>
> I am writing an application that produces avro record files , to be stored on AWS S3 as possible input to EMR.
> I would like to compress with snappy codec before storing them on S3.
> It is my understanding that hadoop currently uses a different snappy codec, mostly used as intermediate map output format .
> My question is how can I generate within my application logic (not MR) snappy compressed avro files?
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