Re: Question about flink message processing guarantee

2015-12-02 Thread Till Rohrmann
Just a small addition. Your sources have to be replayable to some extent.
With replayable I mean that they can continue from some kind of offset.
Otherwise the check pointing won't help you. The Kafka source supports that
for example.

Cheers,
Till
On Dec 1, 2015 11:55 PM, "Márton Balassi"  wrote:

> Dear Jerry,
>
> If you do not enable checkpointing you get the at most once processing
> guarantee (some might call that no guarantee at all). When you enable
> checkpointing you can choose between exactly and at least once semantics.
> The latter provides better latency.
>
> Best,
>
> Marton
>
> On Tue, Dec 1, 2015 at 11:04 PM, Jerry Peng 
> wrote:
>
>> Hello,
>>
>> I have a question regarding link streaming.  I now if you enable
>> checkpointing you can have exactly once processing guarantee. If I do
>> not enable checkpointing what are the semantics of the processing? At
>> least once?
>>
>> Best,
>>
>> Jerry
>>
>
>


Re: Question about flink message processing guarantee

2015-12-02 Thread Stephan Ewen
There is an overview of what guarantees what sources can give you:
https://ci.apache.org/projects/flink/flink-docs-master/apis/fault_tolerance.html#fault-tolerance-guarantees-of-data-sources-and-sinks

On Wed, Dec 2, 2015 at 9:19 AM, Till Rohrmann 
wrote:

> Just a small addition. Your sources have to be replayable to some extent.
> With replayable I mean that they can continue from some kind of offset.
> Otherwise the check pointing won't help you. The Kafka source supports that
> for example.
>
> Cheers,
> Till
> On Dec 1, 2015 11:55 PM, "Márton Balassi" 
> wrote:
>
>> Dear Jerry,
>>
>> If you do not enable checkpointing you get the at most once processing
>> guarantee (some might call that no guarantee at all). When you enable
>> checkpointing you can choose between exactly and at least once semantics.
>> The latter provides better latency.
>>
>> Best,
>>
>> Marton
>>
>> On Tue, Dec 1, 2015 at 11:04 PM, Jerry Peng 
>> wrote:
>>
>>> Hello,
>>>
>>> I have a question regarding link streaming.  I now if you enable
>>> checkpointing you can have exactly once processing guarantee. If I do
>>> not enable checkpointing what are the semantics of the processing? At
>>> least once?
>>>
>>> Best,
>>>
>>> Jerry
>>>
>>
>>


Question about flink message processing guarantee

2015-12-01 Thread Jerry Peng
Hello,

I have a question regarding link streaming.  I now if you enable
checkpointing you can have exactly once processing guarantee. If I do
not enable checkpointing what are the semantics of the processing? At
least once?

Best,

Jerry


Re: Question about flink message processing guarantee

2015-12-01 Thread Márton Balassi
Dear Jerry,

If you do not enable checkpointing you get the at most once processing
guarantee (some might call that no guarantee at all). When you enable
checkpointing you can choose between exactly and at least once semantics.
The latter provides better latency.

Best,

Marton

On Tue, Dec 1, 2015 at 11:04 PM, Jerry Peng 
wrote:

> Hello,
>
> I have a question regarding link streaming.  I now if you enable
> checkpointing you can have exactly once processing guarantee. If I do
> not enable checkpointing what are the semantics of the processing? At
> least once?
>
> Best,
>
> Jerry
>