[jira] [Updated] (FLINK-6472) BoundedOutOfOrdernessTimestampExtractor does not bound out of orderliness

["Aljoscha Krettek (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/FLINK-6472?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Aljoscha Krettek updated FLINK-6472:
------------------------------------
    Component/s:     (was: Streaming)
                 DataStream API

> BoundedOutOfOrdernessTimestampExtractor does not bound out of orderliness
> -------------------------------------------------------------------------
>
>                 Key: FLINK-6472
>                 URL: https://issues.apache.org/jira/browse/FLINK-6472
>             Project: Flink
>          Issue Type: Bug
>          Components: DataStream API
>    Affects Versions: 1.3.0
>            Reporter: Elias Levy
>
> {{BoundedOutOfOrdernessTimestampExtractor}} attempts to emit watermarks that lag behind the largest observed timestamp by a configurable time delta.  It fails to so in some circumstances.
> The class extends {{AssignerWithPeriodicWatermarks}}, which generates watermarks in periodic intervals.  The timer for this intervals is a processing time timer.
> In circumstances where there is a rush of events (restarting Flink, unpausing an upstream producer, loading events from a file, etc), many events with timestamps much larger that what the configured bound would normally allow will be sent downstream without a watermark.  This can have negative effects downstream, as operators may be buffering the events waiting for a watermark to process them, thus leading the memory growth and possible out-of-memory conditions.
> It is probably best to have a bounded out of orderliness extractor that is based on the punctuated timestamp extractor, so we can ensure that watermarks are generated in a timely fashion in event time, with the addition of process time timer to generate a watermark if there has been a lull in events, thus also bounding the delay of generating a watermark in processing time. 



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