hadoop-pig-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Ted Dunning" <ted.dunn...@gmail.com>
Subject Re: [jira] Commented: (PIG-171) Top K
Date Sun, 08 Jun 2008 06:21:12 GMT
An efficient implementation of top K without full histogramming would still
be very, very useful.

On Sat, Jun 7, 2008 at 5:35 PM, Pi Song (JIRA) <jira@apache.org> wrote:

>
>    [
> https://issues.apache.org/jira/browse/PIG-171?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12603350#action_12603350]
>
> Pi Song commented on PIG-171:
> -----------------------------
>
> Seems like all efficient histogram generation algorithms are probabilistic
> so my optimization idea wouldn't work.
>
> > Top K
> > -----
> >
> >                 Key: PIG-171
> >                 URL: https://issues.apache.org/jira/browse/PIG-171
> >             Project: Pig
> >          Issue Type: New Feature
> >            Reporter: Amir Youssefi
> >            Assignee: Amir Youssefi
> >
> > Frequently, users are interested on Top results (especially Top K rows) .
> This can be implemented efficiently in Pig /Map Reduce settings to deliver
> rapid results and low Network Bandwidth/Memory usage.
> >
> >  Key point is to prune all data on the map side and keep only small set
> of rows with Top criteria . We can do it in Algebraic function (combiner)
> with multiple value output. Only a small data-set gets out of mapper node.
> > The same idea is applicable to solve variants of this problem:
> >   - An Algebraic Function for 'Top K Rows'
> >   - An Algebraic Function for 'Top K' values ('Top Rank K' and 'Top Dense
> Rank K')
> >   - TOP K ORDER BY.
> > Another words implementation is similar to combiners for aggregate
> functions but instead of one value we get multiple ones.
> > I will add a sample implementation for Top K Rows and possibly TOP K
> ORDER BY to clarify details.
>
> --
> This message is automatically generated by JIRA.
> -
> You can reply to this email to add a comment to the issue online.
>
>


-- 
ted

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message