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From Fabian Hueske <>
Subject Re: About Stream SQL
Date Sat, 06 Feb 2016 09:28:41 GMT
Excellent! I missed the punctuations in the todo list.

What kind of strategies do you have in mind to handle events that arrive
too late? I see
1. dropping of late events
2. computing an updated window result for each late arriving
element (implies that the window state is stored for a certain period
before it is discarded)
3. computing a delta to the previous window result for each late arriving
element (requires window state as well, not applicable to all aggregation

It would be nice if strategies to handle late-arrivers could be defined in
the query.

I think the plans of the Flink community are quite well aligned with your
ideas for SQL on Streams.
Should we start by updating / extending the Stream document on the Calcite
website to include the new window definitions (TUMBLE, HOP) and a
discussion of punctuations/watermarks/time bounds?


2016-02-06 2:35 GMT+01:00 Julian Hyde <>:

> Let me rephrase: The *majority* of the literature, of which I cited
> just one example, calls them punctuation, and a couple of recent
> papers out of Mountain View doesn't change that.
> There are some fine distinctions between punctuation, heartbeats,
> watermarks and rowtime bounds, mostly in terms of how they are
> generated and propagated, that matter little when planning the query.
> On Fri, Feb 5, 2016 at 5:18 PM, Ted Dunning <> wrote:
> > On Fri, Feb 5, 2016 at 5:10 PM, Julian Hyde <> wrote:
> >
> >> Yes, watermarks, absolutely. The "to do" list has "punctuation", which
> >> is the same thing. (Actually, I prefer to call it "rowtime bound"
> >> because it is feels more like a dynamic constraint than a piece of
> >> data, but the literature[1] calls them punctuation.)
> >>
> >
> > Some of the literature calls them punctuation, other literature [1] calls
> > them watermarks.
> >
> > [1]

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