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https://issues.apache.org/jira/browse/MAHOUT-474?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12898215#action_12898215
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Han Hui Wen commented on MAHOUT-474:
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I have done test for this,
Before using patch,the output of pairwiseSimilarity is 18,7G,
After using patch ,the output of pairwiseSimilarity is about 3.952G( = 247M
*16),
{code}
+ SequenceFileOutputFormat.setCompressOutput(pairwiseSimilarity, true);
+ SequenceFileOutputFormat.setOutputCompressorClass(pairwiseSimilarity,
GzipCodec.class);
+ SequenceFileOutputFormat.setOutputCompressionType(pairwiseSimilarity,
CompressionType.BLOCK);
{code}
Also because RowSimilarityJob run a in separated process ,the properties will
lost from the main Job.
The properties must be set by the RecommenderJob
> Should compress output of Job pairwiseSimilarity and Job asMatrix
> -----------------------------------------------------------------
>
> Key: MAHOUT-474
> URL: https://issues.apache.org/jira/browse/MAHOUT-474
> Project: Mahout
> Issue Type: Improvement
> Components: Collaborative Filtering
> Affects Versions: 0.4
> Reporter: Han Hui Wen
> Assignee: Sean Owen
>
> !https://issues.apache.org/jira/secure/attachment/12451985/RowSimilarityJob-CooccurrencesMapper-SimilarityReducer.jpg!
> From above picture ,we can see that the output of pairwiseSimilarity is very
> large ,we should compress them.
> SequenceFileOutputFormat.setOutputCompressionType(job, style);
> SequenceFileOutputFormat.setCompressOutput(job, compress);
> SequenceFileOutputFormat.setOutputCompressorClass(job, codecClass)
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