@Tyler, Yes, the difficulty is to define that trigger. The existing triggers fire at the end of window. (I could be mistaken, which will be good news)
@Ben, B and C which are not mutually exclusive More on my use case. Say a user visits http://foo at 1, http://foo/bar at 4 and back to http://foo at 5 all in a Session we would want to emit http://foo when the watermark passes 1 http://foo -> http://foo/bar when the watermark passes 4 http://foo -> http://foo/bar -> http://foo when the watermark passes 5 On Fri, Dec 2, 2016 at 10:12 AM Ben Chambers <[email protected]> wrote: > As a clarifying question: > > If you have three elements in the pane with timestamps [1, 4, 5], would > you: > A. want to emit that entire pane when the watermark passes 1 > B. want to emit that entire pane when the watermark passes 5 > C. emit a fragment of that pane containing only the first element when the > watermark passes 1 > > On Thu, Dec 1, 2016 at 6:01 PM Tyler Akidau <[email protected]> wrote: > > So what you want is essentially a trigger that fires when the watermark > has passed the event time of the oldest un-emitted element in the current > pane? You could them presumably wrap this in a repeat to get the overall > desired semantics, right? > > -Tyler > > > On Fri, Dec 2, 2016 at 7:32 AM Manu Zhang <[email protected]> wrote: > > My use case is to track user trajectory based on page view event when they > visit a website. The input would be like a list of PageView(userId, url, > eventTimestamp) with watermarks (= eventTimestamp - duration). I'm trying > Sessions with event time trigger. Note we can't wait for the end of session > window due to latency requirement. Instead, we want to emit the user > trajectories whenever a buffered PageView's event time is passed by > watermark. > > On Fri, Dec 2, 2016 at 5:41 AM Lukasz Cwik <[email protected]> wrote: > > Can you provide more details about the problem your trying to solve with > some examples showing input and the expected output? > > > > > On Wed, Nov 30, 2016 at 11:08 PM, Manu Zhang <[email protected]> > wrote: > > Hi, > > Recently I’m addressing a problem where users want to trigger after > watermark past each element (i.e. in the middle of event-time window). I > fail to find an existing trigger that does so. Any idea on model this > problem with Beam ? > > Thanks, > Manu Zhang > > >
