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https://issues.apache.org/jira/browse/PIG-1062?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12772704#action_12772704
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Thejas M Nair commented on PIG-1062:
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As indicated in previous comment, I am planning to go ahead with the [earlier
proposal|https://issues.apache.org/jira/browse/PIG-1062?focusedCommentId=12772197&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#action_12772197]
. The current sample frequency would be one tuple every ( (H/s) * (1/17) )
tuples.
In PartitionSkewedKey.exec(), the number of reducers for join key k1 can be
computed using (no_of_samples(k1) / 17) . But the accuracy of this calculation
depends on how accurate the average tuple size computed is (s in (H/s) *
(1/17)). Sending a special tuple with number of rows in the split will likely
lead to more accurate estimate of number of reducers required.
> load-store-redesign branch: change SampleLoader and subclasses to work with
> new LoadFunc interface
> ---------------------------------------------------------------------------------------------------
>
> Key: PIG-1062
> URL: https://issues.apache.org/jira/browse/PIG-1062
> Project: Pig
> Issue Type: Sub-task
> Reporter: Thejas M Nair
> Assignee: Thejas M Nair
>
> This is part of the effort to implement new load store interfaces as laid out
> in http://wiki.apache.org/pig/LoadStoreRedesignProposal .
> PigStorage and BinStorage are now working.
> SampleLoader and subclasses -RandomSampleLoader, PoissonSampleLoader need to
> be changed to work with new LoadFunc interface.
> Fixing SampleLoader and RandomSampleLoader will get order-by queries working.
> PoissonSampleLoader is used by skew join.
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