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https://issues.apache.org/jira/browse/FLINK-5185?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15709903#comment-15709903
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Fabian Hueske commented on FLINK-5185:
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I assume, you are proposing this in order to create a {{BatchTableSourceScan}}
with pushed down predicate or projection, right?
In this case, you would need to create a new {{TableSourceTable}} to hold the
modified {{TableSource}} which projects and/or filters in the {{RelOptRule}}
that translates {{LogicalScan}} and {{LogicalCalc}} to {{BatchTableSourceScan}}.
How about we just add optional parameters for projection columns and filter
conditions to the {{BatchTableSouceScan}} and generate the modified
{{TableSource}} inside of the {{BatchTableSouceScan.translateToPlan()}} method?
Then we would not need to create a new {{TableSource}} in a {{RelOptRule}} at
all but would do this when the plan is generated.
> Decouple BatchTableSourceScan with TableSourceTable
> ---------------------------------------------------
>
> Key: FLINK-5185
> URL: https://issues.apache.org/jira/browse/FLINK-5185
> Project: Flink
> Issue Type: Improvement
> Components: Table API & SQL
> Affects Versions: 1.2.0
> Reporter: Kurt Young
> Assignee: zhangjing
> Priority: Minor
>
> As the components' relationship show in this design doc:
> https://docs.google.com/document/d/1PBnEbOcFHlEF1qGGAUgJvINdEXzzFTIRElgvs4-Tdeo/
> We found it's been annoying for {{BatchTableSourceScan}} directly holding
> {{TableSourceTable}}, and refer to {{TableSource}} further. It's ok if the
> relationship is immutable, but when we want to change the {{TableSource}}
> when applying optimizations, it will cause some conflicts and
> misunderstanding.
> Since there is only one way to change {{TableSource}}, which is creating a
> new {{TableSourceTable}} to hold the new {{TableSource}}, and create a new
> {{BatchTableSourceScan}} pointing to the {{TableSourceTable}} which just
> created. The annoying part is the {{RelOptTable}} comes from the super class
> {{TableScan}} still holds the connection to the original {{TableSourceTable}}
> and {{TableSource}}. It will cause some misunderstanding, which one should
> the {{Scan}} rely to, and what's difference between these tables.
> Besides, {{TableSourceTable}} is not very useful in {{BatchTableSourceScan}},
> the only thing {{Scan}} cares is the {{RowType}} it returns, since this is
> and should be decided by {{TableSource}}. So we can let
> {{BatchTableSourceScan}} directly holding {{TableSource}} instead of holding
> {{TableSourceTable}}.If some original information are needed, find table
> through {{RelOptTable}}.
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