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Posted to dev@kylin.apache.org by "Prashant Prakash (JIRA)" <ji...@apache.org> on 2016/01/12 04:34:39 UTC
[jira] [Created] (KYLIN-1304) Incorrect count estimate upon
HyperLogLogPlusCounter.merge operation.
Prashant Prakash created KYLIN-1304:
---------------------------------------
Summary: Incorrect count estimate upon HyperLogLogPlusCounter.merge operation.
Key: KYLIN-1304
URL: https://issues.apache.org/jira/browse/KYLIN-1304
Project: Kylin
Issue Type: Bug
Affects Versions: v1.1.1
Reporter: Prashant Prakash
We are using hllc12 for evaluating uniques for a measure in a table partitioned over date.
The uniques estimate for individual dates 2016-01-07, 2016-01-08, 2016-01-09 are 93,728,324, 90,982,364, 45,485,278 respectively.
But the uniques across days, which is calculated through HyperLogLogPlusCounter.merge operation gives a incorrect value 67,980,576.
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Re: [jira] [Created] (KYLIN-1304) Incorrect count estimate upon
HyperLogLogPlusCounter.merge operation.
Posted by hongbin ma <ma...@apache.org>.
liyang owns the HLL code, I have assigned the JIRA to him
On Wed, Jan 13, 2016 at 12:27 PM, vipul jhawar <vi...@gmail.com>
wrote:
> Hi Luke
>
> Please check this issue once and let us know if merging HLL for uniques has
> been stable for you guys as we recently saw a huge discrepancy and wanted
> to check with you guys if we should totally avoid this option for now or we
> can bank upon it.
>
> Thanks
>
> On Tue, Jan 12, 2016 at 9:04 AM, Prashant Prakash (JIRA) <ji...@apache.org>
> wrote:
>
> > Prashant Prakash created KYLIN-1304:
> > ---------------------------------------
> >
> > Summary: Incorrect count estimate upon
> > HyperLogLogPlusCounter.merge operation.
> > Key: KYLIN-1304
> > URL: https://issues.apache.org/jira/browse/KYLIN-1304
> > Project: Kylin
> > Issue Type: Bug
> > Affects Versions: v1.1.1
> > Reporter: Prashant Prakash
> >
> >
> > We are using hllc12 for evaluating uniques for a measure in a table
> > partitioned over date.
> > The uniques estimate for individual dates 2016-01-07, 2016-01-08,
> > 2016-01-09 are 93,728,324, 90,982,364, 45,485,278 respectively.
> > But the uniques across days, which is calculated through
> > HyperLogLogPlusCounter.merge operation gives a incorrect value
> 67,980,576.
> >
> >
> >
> >
> > --
> > This message was sent by Atlassian JIRA
> > (v6.3.4#6332)
> >
>
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Regards,
*Bin Mahone | 马洪宾*
Apache Kylin: http://kylin.io
Github: https://github.com/binmahone
Re: [jira] [Created] (KYLIN-1304) Incorrect count estimate upon
HyperLogLogPlusCounter.merge operation.
Posted by vipul jhawar <vi...@gmail.com>.
Hi Luke
Please check this issue once and let us know if merging HLL for uniques has
been stable for you guys as we recently saw a huge discrepancy and wanted
to check with you guys if we should totally avoid this option for now or we
can bank upon it.
Thanks
On Tue, Jan 12, 2016 at 9:04 AM, Prashant Prakash (JIRA) <ji...@apache.org>
wrote:
> Prashant Prakash created KYLIN-1304:
> ---------------------------------------
>
> Summary: Incorrect count estimate upon
> HyperLogLogPlusCounter.merge operation.
> Key: KYLIN-1304
> URL: https://issues.apache.org/jira/browse/KYLIN-1304
> Project: Kylin
> Issue Type: Bug
> Affects Versions: v1.1.1
> Reporter: Prashant Prakash
>
>
> We are using hllc12 for evaluating uniques for a measure in a table
> partitioned over date.
> The uniques estimate for individual dates 2016-01-07, 2016-01-08,
> 2016-01-09 are 93,728,324, 90,982,364, 45,485,278 respectively.
> But the uniques across days, which is calculated through
> HyperLogLogPlusCounter.merge operation gives a incorrect value 67,980,576.
>
>
>
>
> --
> This message was sent by Atlassian JIRA
> (v6.3.4#6332)
>