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From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (FLINK-6352) FlinkKafkaConsumer should support to use timestamp to set up start offset
Date Thu, 11 Jan 2018 12:15:00 GMT

    [ https://issues.apache.org/jira/browse/FLINK-6352?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16322119#comment-16322119
] 

ASF GitHub Bot commented on FLINK-6352:
---------------------------------------

Github user tzulitai commented on the issue:

    https://github.com/apache/flink/pull/3915
  
    Hi @zjureel, I went ahead to address my own review / concerns with the change in another
PR that is based on your current work: #5282. I hope that is okay, and would be great if you
would like to review that.
    
    The main changes are:
    - We eagerly determine the timestamp offsets. `LATEST`, `EARLIEST`, `GROUP_OFFSETS` startup
modes still determines the offsets lazily, while `TIMESTAMP` and `SPECIFIC_OFFSETS` will have
actual offsets already before they handled by the `KafkaConsumerThread`. It dawned on me that
actually there is no reason to lazily determine the offset for timestamp-based startup, since
the actual offset in the end in this case does not vary depending on when we fetch the startup
offsets.
    - Don't use `Date` to define timestamp, just use Longs. The Kafka APIs actually take long
value timestamps, so I figured it would make sense that we follow. 


> FlinkKafkaConsumer should support to use timestamp to set up start offset
> -------------------------------------------------------------------------
>
>                 Key: FLINK-6352
>                 URL: https://issues.apache.org/jira/browse/FLINK-6352
>             Project: Flink
>          Issue Type: Improvement
>          Components: Kafka Connector
>            Reporter: Fang Yong
>            Assignee: Fang Yong
>            Priority: Blocker
>             Fix For: 1.5.0
>
>
>     Currently "auto.offset.reset" is used to initialize the start offset of FlinkKafkaConsumer,
and the value should be earliest/latest/none. This method can only let the job comsume the
beginning or the most recent data, but can not specify the specific offset of Kafka began
to consume. 
>     So, there should be a configuration item (such as "flink.source.start.time" and the
format is "yyyy-MM-dd HH:mm:ss") that allows user to configure the initial offset of Kafka.
The action of "flink.source.start.time" is as follows:
> 1) job start from checkpoint / savepoint
>   a> offset of partition can be restored from checkpoint/savepoint,  "flink.source.start.time"
will be ignored.
>   b> there's no checkpoint/savepoint for the partition (For example, this partition
is newly increased), the "flink.kafka.start.time" will be used to initialize the offset of
the partition    
> 2) job has no checkpoint / savepoint, the "flink.source.start.time" is used to initialize
the offset of the kafka
>   a> the "flink.source.start.time" is valid, use it to set the offset of kafka
>   b> the "flink.source.start.time" is out-of-range, the same as it does currently
with no initial offset, get kafka's current offset and start reading



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