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From Konstantin Knauf <konstan...@ververica.com>
Subject Re: Flink session window not progressing
Date Mon, 29 Apr 2019 19:28:59 GMT
Hi Henrik,

yes, the output count of a sink (and the input count of sources) is always
zero, because only Flink internal traffic is reflected in these metrics.
There is a Jira issue to change this [1].



[1] https://issues.apache.org/jira/browse/FLINK-7286

On Mon, Apr 29, 2019 at 7:29 PM Henrik Feldt <henrik.feldt@voiapp.io> wrote:

> Thinking more about this; it might just be me who is reacting to the sink
> having a zero rate of output. In fact, I have about two gigs of messages
> left in the queue until it's up to date, so I may just be running a slow
> calculation (because I've run a batch job to backfill to after stream).
> Perhaps something is broken about sink output counts?
> On 29 Apr 2019, at 19:26, Henrik Feldt wrote:
> Hi guys,
> I'm going a PoC with Flink and I was wondering if you could help me.
> I've asked a question here
> https://stackoverflow.com/questions/55907954/flink-session-window-sink-timestamp-not-progressing
> with some images. However, in summary my question is this; why doesn't my
> session window progress?
> It works great when I run it against historical data, but when I run it
> against a streaming data source (pub/sub) it sometimes gets stuck. In this
> case, it got stuck at exactly 12:00 UTC.
> My window is a session window, but one where I bump the last 'edge' of the
> window by different amounts depending on what event type it is. Because
> some events never have other events after them.
> You can see the problem the easiest in these graphs, specifically the one
> that stops at 14:00 CEST (12:00 UTC) - with green bars.
> This graph shows the low-watermark progressing throughout the node in the
> middle (which is also a sink); and this holds for all the nodes in the
> graph. However, the session windowing doesn't progress, despite the
> low-watermark progressing.
> Regards,
> Henrik


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