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https://issues.apache.org/jira/browse/FLINK-7446?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16179066#comment-16179066
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ASF GitHub Bot commented on FLINK-7446:
---------------------------------------
Github user twalthr commented on a diff in the pull request:
https://github.com/apache/flink/pull/4710#discussion_r140771682
--- Diff: docs/dev/table/streaming.md ---
@@ -336,27 +336,24 @@ val windowedTable = tEnv
### Event time
-Event time allows a table program to produce results based on the time
that is contained in every record. This allows for consistent results even in
case of out-of-order events or late events. It also ensures replayable results
of the table program when reading records from persistent storage.
+Event time allows a table program to produce results based on the time
that is contained in every record. This allows for consistent results even in
case of out-of-order events or late events. It also ensures replayable results
of the table program when reading records from persistent storage.
Additionally, event time allows for unified syntax for table programs in
both batch and streaming environments. A time attribute in a streaming
environment can be a regular field of a record in a batch environment.
In order to handle out-of-order events and distinguish between on-time and
late events in streaming, Flink needs to extract timestamps from events and
make some kind of progress in time (so-called [watermarks]({{ site.baseurl
}}/dev/event_time.html)).
An event time attribute can be defined either during DataStream-to-Table
conversion or by using a TableSource.
-The Table API & SQL assume that in both cases timestamps and watermarks
have been generated in the [underlying DataStream API]({{ site.baseurl
}}/dev/event_timestamps_watermarks.html) before. Ideally, this happens within a
`TableSource` with knowledge about the incoming data's characteristics and is
hidden from the end user of the API.
-
-
#### During DataStream-to-Table Conversion
-The event time attribute is defined with the `.rowtime` property during
schema definition.
+The event time attribute is defined with the `.rowtime` property during
schema definition. Timestamps and watermarks must have been assigned in the
`DataStream` that is converted.
--- End diff --
Add a link to `dev/event_timestamps_watermarks` again?
> Support to define an existing field as the rowtime field for TableSource
> ------------------------------------------------------------------------
>
> Key: FLINK-7446
> URL: https://issues.apache.org/jira/browse/FLINK-7446
> Project: Flink
> Issue Type: Improvement
> Components: Table API & SQL
> Reporter: Jark Wu
> Assignee: Fabian Hueske
>
> Currently {{DefinedRowtimeAttribute}} can define an appended rowtime field
> for a {{TableSource}}. But it would be helpful if we can support to define an
> existing field as the rowtime field. Just like registering a DataStream, the
> rowtime field can be appended but also can replace an existing field.
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