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https://issues.apache.org/jira/browse/FLINK-22456?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ASF GitHub Bot updated FLINK-22456:
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    Labels: pull-request-available  (was: )

> Support InitializeOnMaster and FinalizeOnMaster to be used in InputFormat
> -------------------------------------------------------------------------
>
>                 Key: FLINK-22456
>                 URL: https://issues.apache.org/jira/browse/FLINK-22456
>             Project: Flink
>          Issue Type: Improvement
>          Components: Runtime / Task
>            Reporter: Li
>            Priority: Minor
>              Labels: pull-request-available
>
>         In _InputOutputFormatVertex_, _initializeGlobal_ and _finalizeGlobal_ 
> are only called when the Format is _OutputFormat_, however _InputFormat_ is 
> not be called.
>         In FLINK-1722, its say _HadoopOutputFormats_ ues it to do something 
> before and after the task. And they only support _initializeGlobal_ and 
> _finalizeGlobal_ in _OutputFormat_.
>         I don't know why _InputFormat_ doesn't support, anyone can tell me 
> why?
>         But I think _InitializeOnMaster_ and _FinalizeOnMaster_ should also 
> be supported in _InputFormat_.
>         For example, an offline task in _JdbcInputFormat_, user can use 
> _initializeGlobal_ to query the total counts of this task, and then user can 
> create InputSplits by total counts. While task running, user can add progress 
> indicators metric by calculating the total number of records divided by the 
> current number of reads, and even the remaining time of the task can be 
> estimated. It is very helpful for users to view task progress and remaining 
> time through external systems.



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