flink-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From aljoscha <...@git.apache.org>
Subject [GitHub] flink pull request #3191: [FLINK-5529] [FLINK-4752] [docs] Improve / extends...
Date Wed, 25 Jan 2017 17:32:12 GMT
Github user aljoscha commented on a diff in the pull request:

    --- Diff: docs/dev/windows.md ---
    @@ -622,133 +690,138 @@ input
    -## Dealing with Late Data
    +## Triggers
    -When working with event-time windowing it can happen that elements arrive late, i.e the
    -watermark that Flink uses to keep track of the progress of event-time is already past
    -end timestamp of a window to which an element belongs. Please
    -see [event time](./event_time.html) and especially
    -[late elements](./event_time.html#late-elements) for a more thorough discussion of
    -how Flink deals with event time.
    +A `Trigger` determines when a window (as formed by the `WindowAssigner`) is ready to
    +processed by the *window function*. Each `WindowAssigner` comes with a default `Trigger`.

    +If the default trigger does not fit your needs, you can specify a custom trigger using
    -You can specify how a windowed transformation should deal with late elements and how
much lateness
    -is allowed. The parameter for this is called *allowed lateness*. This specifies by how
much time
    -elements can be late. Elements that arrive within the allowed lateness are still put
into windows
    -and are considered when computing window results. If elements arrive after the allowed
lateness they
    -will be dropped. Flink will also make sure that any state held by the windowing operation
is garbage
    -collected once the watermark passes the end of a window plus the allowed lateness.
    +The trigger interface provides five methods that react to different events: 
    --- End diff --
    I think it doesn't "provide" the methods, maybe write "The trigger interface has five
methods that allow a Trigger to react to different events"

If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastructure@apache.org or file a JIRA ticket
with INFRA.

View raw message