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https://issues.apache.org/jira/browse/CALCITE-1227?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15309877#comment-15309877
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zhen wang commented on CALCITE-1227:
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I updated PR with one possible solution. don't quite like it though as the 
dataContext are hacked into Statement.
possibly elegant ways to do this. but that's what I understand. 

the `throw unsupported` in the cancel handling suggests `cancel` haven't been 
considered thoroughly throughout the execution stage. 

and another issue is that, enumerator read one more record after CTRL+C is 
pressed.  this might not be desired. 

> Add streaming CSV table
> -----------------------
>
>                 Key: CALCITE-1227
>                 URL: https://issues.apache.org/jira/browse/CALCITE-1227
>             Project: Calcite
>          Issue Type: Bug
>            Reporter: Julian Hyde
>            Assignee: Julian Hyde
>
> Add a variant of CsvTable that can be streamed. It would serve as an example 
> of how to write stream adapters.
> It would be like the CSV adapter, but watches a file and reports records 
> added to the end of the file (like the tail command). 
> You’d have to change {{CsvTable}} to implement {{StreamableTable}}, and 
> implement the {{Table stream()}} method to return a variant of the table that 
> is in “follow” mode.
> It would probably be implemented by a variant of CsvEnumerator, but it is 
> getting its input in bursts, as the file is appended to.
> You would still be able to use this adapter to read historical data from the 
> CSV file. Appending records to the file would make a nice demo.



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