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?
---