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Re: when plan to implemnt merge operation

Posted by Liang Chen-2 on May 29, 2017; 1:13pm
URL: http://apache-carbondata-dev-mailing-list-archive.168.s1.nabble.com/when-plan-to-implemnt-merge-operation-tp13228p13395.html

Hi

For your this case,  use delete and append whether can meet your
requirements?

Obviously , merge would impact index, so we should find out one best way to
implement this feature.
please other people give some comment also.

Regards
Liang


2017-05-27 9:45 GMT+08:00 Mic Sun <[hidden email]>:

> merge example like this:
> small:
> id   updatatime
> 1       9:00
> 2       8:00
> 6       9:00
>
> big:
> id   updatetime
> 1      10:00
> 2      7:00
> 3      9:00
> 4      9:00
> 5      9:00
>
> as for record in small:
> id=1,small.update<big.update,do nothing;
> id=2,small.update>bigdate.update,update big;
> id=6,big doesn't have that record,insert big;
>
> for our solution:
> append all small record to big,
> big:
> id   updatetime
> 1      10:00
> 2      7:00(to be delete)
> 3      9:00
> 4      9:00
> 5      9:00
> 1      9:00(to be deleted)
> 2      8:00
> 6      9:00
> then,for records in big which have the same id,max updatetime stays.
>
>
>
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