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https://issues.apache.org/jira/browse/KYLIN-2353?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16640322#comment-16640322
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Ruslan Dautkhanov commented on KYLIN-2353:
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[~kangkaisen] thank you for this great improvement.
Would you recommend bitmapCounter for highly-cardinal columns?
I assume it will work super fast for low-cardinal columns like `product type`,
but would
it work on highly cardinal columns, let's say if number of distintinct values
in a column
`household_id` is *1 billion*, would Bitmap Counter and Kylin general handle
`count(distinct household_id)` very well?
> Serialize BitmapCounter with distinct count
> -------------------------------------------
>
> Key: KYLIN-2353
> URL: https://issues.apache.org/jira/browse/KYLIN-2353
> Project: Kylin
> Issue Type: Improvement
> Components: Metadata
> Affects Versions: v1.6.0
> Reporter: kangkaisen
> Assignee: kangkaisen
> Priority: Major
> Fix For: v2.0.0
>
> Attachments: KYLIN-2353.patch
>
>
> Currently, we deserialize the bitmap whether we need to aggregate or not.
> Actually, we could serialize {{BitmapCounter}} with bitmap counter and delay
> to deserialize bitmap until we need to aggregate bitmap and only get the
> counter for the bitmap when deserialize.
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