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https://issues.apache.org/jira/browse/FLINK-7548?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16171634#comment-16171634
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Jark Wu commented on FLINK-7548:
--------------------------------
Hi [~fhueske], thanks for the proposal. I really like it ! It meets most of our
requirement. I have some additional thoughts:
Regarding to the existing field type, should we support {{Timestamp}} type?
Timestamp is a very common type in traditional database.
The computed timestamp is a very useful feature. We implemented it in Blink SQL
which is called "Computed Column", it is a new field which is computed based on
one or more existing fields. The computed column can be used as timestamp field
but also a normal field. The computed column is computed using an expression
(including UDF). What about to make TableSource support "Computed Column"
instead of UDF converter?
{quote}
preserve type of time indicator fields. At the moment, a field of type
ROWTIME_INDICATOR is exposed to the user as TIMESTAMP. However, a time field is
initially be of type LONG such that the type exposed to the user is changed. We
might want to add a time indicator that exposes itself as LONG.
{quote}
I agree to preserve the type. It is very strange that a long type field becomes
{{Timestamp}} type when treat the field as timestamp field.
What do you think about this [~fhueske], [~xccui], [~wheat9] ?
> Support watermark generation for TableSource
> --------------------------------------------
>
> Key: FLINK-7548
> URL: https://issues.apache.org/jira/browse/FLINK-7548
> Project: Flink
> Issue Type: Bug
> Components: Table API & SQL
> Reporter: Jark Wu
>
> As discussed in FLINK-7446, currently the TableSource only support to define
> rowtime field, but not support to extract watermarks from the rowtime field.
> We can provide a new interface called {{DefinedWatermark}}, which has two
> methods {{getRowtimeAttribute}} (can only be an existing field) and
> {{getWatermarkGenerator}}. The {{DefinedRowtimeAttribute}} will be marked
> deprecated.
> How to support periodic and punctuated watermarks and support some built-in
> strategies needs further discussion.
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