[ 
https://issues.apache.org/jira/browse/FLINK-5479?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Tzu-Li (Gordon) Tai updated FLINK-5479:
---------------------------------------
    Description: 
Reported in ML: 
http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/Kafka-topic-partition-skewness-causes-watermark-not-being-emitted-td11008.html

Similar to what's happening to idle sources blocking watermark progression in 
downstream operators (see FLINK-5017), the per-partition watermark mechanism in 
{{FlinkKafkaConsumer}} is also being blocked of progressing watermarks when a 
partition is idle. The watermark of idle partitions is always 
{{Long.MIN_VALUE}}, therefore the overall min watermark across all partitions 
of a consumer subtask will never proceed.

It's normally not a common case to have Kafka partitions not producing any 
data, but it'll probably be good to handle this as well. I think we should have 
a localized solution similar to FLINK-5017 for the per-partition watermarks in 
{{AbstractFetcher}}.

  was:
Reported in ML: 
http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/Kafka-topic-partition-skewness-causes-watermark-not-being-emitted-td11008.html

Similar to what's happening to idle sources blocking watermark progression in 
downstream operators (see FLINK-5017), the per-partition watermark mechanism in 
`FlinkKafkaConsumer` is also being blocked of progressing watermarks when a 
partition is idle. The watermark of idle partitions is always `Long.MIN_VALUE`, 
therefore the overall min watermark across all partitions of a consumer subtask 
will never proceed.

It's normally not a common case to have Kafka partitions not producing any 
data, but it'll probably be good to handle this as well. I think we should have 
a localized solution similar to FLINK-5017 for the per-partition watermarks in 
`AbstractFetcher`.


> Per-partition watermarks in FlinkKafkaConsumer should consider idle partitions
> ------------------------------------------------------------------------------
>
>                 Key: FLINK-5479
>                 URL: https://issues.apache.org/jira/browse/FLINK-5479
>             Project: Flink
>          Issue Type: Improvement
>          Components: Kafka Connector
>            Reporter: Tzu-Li (Gordon) Tai
>             Fix For: 1.3.0
>
>
> Reported in ML: 
> http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/Kafka-topic-partition-skewness-causes-watermark-not-being-emitted-td11008.html
> Similar to what's happening to idle sources blocking watermark progression in 
> downstream operators (see FLINK-5017), the per-partition watermark mechanism 
> in {{FlinkKafkaConsumer}} is also being blocked of progressing watermarks 
> when a partition is idle. The watermark of idle partitions is always 
> {{Long.MIN_VALUE}}, therefore the overall min watermark across all partitions 
> of a consumer subtask will never proceed.
> It's normally not a common case to have Kafka partitions not producing any 
> data, but it'll probably be good to handle this as well. I think we should 
> have a localized solution similar to FLINK-5017 for the per-partition 
> watermarks in {{AbstractFetcher}}.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Reply via email to