Re: the group key is retracted
Posted by
lec ssmi on
URL: http://deprecated-apache-flink-user-mailing-list-archive.369.s1.nabble.com/the-group-key-is-retracted-tp36288p36294.html
The old value is already counted in a partition, and when the above update occurs, will the count value of the old partition be subtracted by 1, and then added to the new partition?
Hi lec ssmi,
> If the type value of a record is updated in the database, the values before and after the update will be divided into different partitions and handed over to different operators for calculation.
I think your understanding is correct.
> Can Retraction happen correctly?
I didn't get your point, can you elaborate your question a little bit?
Hi:
When we use sql for aggregation operation, for example, the following sql
select count( distinct name) cnt, type from table group by type
Source data can be regarded as bin log data.
If the type value of a record is updated in the database, the values before and after the update will be divided into different partitions and handed over to different operators for calculation. Can Retraction happen correctly?
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