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https://issues.apache.org/jira/browse/FLINK-14807?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17046394#comment-17046394
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Kurt Young edited comment on FLINK-14807 at 2/27/20 9:30 AM:
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{quote}The communication channel is always needed whether it is exactly once or
not. Exactly once semantic (EOS) requires additional protocol on top of the
basic communication channel. When I say it is simpler, I meant the protocol
would be simpler.
{quote}
Not really, EOS will be required anyway no matter we are dealing with client
failure or not. Imagine we are retrieving the result of batch job, and when
client started to get results back from the sink, the sink operator failed and
restart. We have to retrieve the whole result again and also need a way to tell
the client the previous results are invalid.
was (Author: ykt836):
{quote}The communication channel is always needed whether it is exactly once or
not. Exactly once semantic (EOS) requires additional protocol on top of the
basic communication channel. When I say it is simpler, I meant the protocol
would be simpler.
{quote}
Not really, EOS will be required anyway whether we are dealing with client
failure or not. Imagine we are retrieving the result of batch job, and when
client started to get results back from the sink, the sink operator failed and
restart. We have to retrieve the whole result again and also need a way to tell
the client the previous results are invalid.
> Add Table#collect api for fetching data to client
> -------------------------------------------------
>
> Key: FLINK-14807
> URL: https://issues.apache.org/jira/browse/FLINK-14807
> Project: Flink
> Issue Type: New Feature
> Components: Table SQL / API
> Affects Versions: 1.9.1
> Reporter: Jeff Zhang
> Priority: Major
> Labels: usability
> Fix For: 1.11.0
>
> Attachments: table-collect.png
>
>
> Currently, it is very unconvinient for user to fetch data of flink job unless
> specify sink expclitly and then fetch data from this sink via its api (e.g.
> write to hdfs sink, then read data from hdfs). However, most of time user
> just want to get the data and do whatever processing he want. So it is very
> necessary for flink to provide api Table#collect for this purpose.
>
> Other apis such as Table#head, Table#print is also helpful.
>
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