Re: when plan to implemnt merge operation

Posted by 孙而焓 on
URL: http://apache-carbondata-dev-mailing-list-archive.168.s1.nabble.com/when-plan-to-implemnt-merge-operation-tp13228p13288.html

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.