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From Sameer W <sam...@axiomine.com>
Subject Default timestamps for Event Time when no Watermark Assigner used?
Date Tue, 23 Aug 2016 10:42:21 GMT
Hi,

If you do not explicitly assign timestamps and watermarks when using Event
Time, does it automatically default to using Ingestion Time?

I was reading the Kinesis integration section and came across the note
below and which raised the above question. I saw another place where you
explicitly use Event Time with ingestion time with the following
- .assignTimestampsAndWatermarks(new IngestionTimeExtractor<>());.

Does that line have to called explicitly or is it the default?


"If streaming topologies choose to use the event time notion
<https://ci.apache.org/projects/flink/flink-docs-master/apis/streaming/event_time.html>
for
record timestamps, an *approximate arrival timestamp* will be used by
default. This timestamp is attached to records by Kinesis once they were
successfully received and stored by streams. Note that this timestamp is
typically referred to as a Kinesis server-side timestamp, and there are no
guarantees about the accuracy or order correctness (i.e., the timestamps
may not always be ascending)."

Thanks,
Sameer

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