Hi!

- I'm currently running my flink program on 1.2 SNAPSHOT with kafka source and 
I have checkpoint enabled. When I look at the consumer offsets in kafka it 
appears to be stagnant and there is a huge lag. But I can see my flink program 
is in pace with kafka source in JMX metrics and outputs. Is there a way to 
identify why the offsets are not committed to kafka?

On which commit was your Kafka connector built? There was a recent change to 
the offset committing for Kafka 0.9 consumer, so identifying the exact commit 
will help clarify whether the recent change introduced any new problems. Also, 
what is your configured checkpoint interval? When checkpointing is enabled, the 
Kafka consumer only commits to Kafka when checkpoints are completed. So, 
offsets in Kafka are not updated until the next checkpoint is triggered.

- In my current application we custom loggers for debugging purposes. Let’s say 
we want to find what’s happening for a particular user, we fire an api request 
to add the custom logger for that particular user and use it for logging along 
the data path. Is there a way to achieve this in flink? Are there any global 
mutable parameters that I can use to achieve this functionality?

I’m not sure if I understand the use case correctly, but it seems like you will 
need to change configuration / behaviour of a specific Flink operator at 
runtime. To my knowledge, the best way to do this in Flink right now is to 
translate your original logging-trigger api requests to a stream of events fed 
to Flink. This stream of events will then basically be changes of your user 
logger behaviour, and your operators can change its logging behaviour according 
to this stream.

- Can I pass on state between operators? If I need the state stored on previous 
operators, how can I fetch it?

I don’t think this is possible.


Best Regards,
Gordon


On October 3, 2016 at 2:08:31 PM, Govindarajan Srinivasaraghavan 
(govindragh...@gmail.com) wrote:

Hi,

 

I have few questions on how I need to model my use case in flink. Please 
advise. Thanks for the help.

 

- I'm currently running my flink program on 1.2 SNAPSHOT with kafka source and 
I have checkpoint enabled. When I look at the consumer offsets in kafka it 
appears to be stagnant and there is a huge lag. But I can see my flink program 
is in pace with kafka source in JMX metrics and outputs. Is there a way to 
identify why the offsets are not committed to kafka?

 

- In my current application we custom loggers for debugging purposes. Let’s say 
we want to find what’s happening for a particular user, we fire an api request 
to add the custom logger for that particular user and use it for logging along 
the data path. Is there a way to achieve this in flink? Are there any global 
mutable parameters that I can use to achieve this functionality?

 

- Can I pass on state between operators? If I need the state stored on previous 
operators, how can I fetch it?

 

Thanks

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