?????? why we need keyed state and operate state when we already have checkpoint?

[??????]

Thanks for your replies,I have some understandings.


There are two cases.
1. if I use no keyed state in program,when it's killed,I can only resume from 
previous result
1. if I use      keyed state in program,when it's killed,I 
can         resume from previous result and previous 
variable temporary result.


Am I right?
Thanks for your guide.




------------------ ???????? ------------------
??????:                                                                         
                                               "Arvid Heise"                    
                                                                
<ar...@ververica.com&gt;;
????????:&nbsp;2020??10??7??(??????) ????2:25
??????:&nbsp;"??????"<appleyu...@foxmail.com&gt;;
????:&nbsp;"Shengkai 
Fang"<fskm...@gmail.com&gt;;"user"<user@flink.apache.org&gt;;
????:&nbsp;Re: why we need keyed state and operate state when we already have 
checkpoint?



I think there is some misunderstanding here: a checkpoint IS (a snapshot of) 
the keyed state and operator state (among a few more things). [1]


[1]&nbsp;https://ci.apache.org/projects/flink/flink-docs-release-1.11/learn-flink/fault_tolerance.html#definitions


On Wed, Oct 7, 2020 at 6:51 AM ?????? <appleyu...@foxmail.com&gt; wrote:

when the job is killed,state is also misssing.
so why we need keyed state?Is keyed state useful when we try to resuming the 
killed job?




------------------&nbsp;????????&nbsp;------------------
??????:                                                                         
                                               "Shengkai Fang"                  
                                                                  
<fskm...@gmail.com&gt;;
????????:&nbsp;2020??10??7??(??????) ????12:43
??????:&nbsp;"??????"<appleyu...@foxmail.com&gt;;
????:&nbsp;"user"<user@flink.apache.org&gt;;
????:&nbsp;Re: why we need keyed state and operate state when we already have 
checkpoint?



The checkpoint is a snapshot for the job and we can resume the job if the job 
is killed unexpectedly. The state is another thing to memorize the intermediate 
result of calculation. I don't think the checkpoint can replace state.

?????? <appleyu...@foxmail.com&gt; ??2020??10??7?????? ????12:26??????

Could you tell me:


why we need keyed state and operator state when we already have checkpoint?

when a running jar crash,we can resume from the checkpoint 
automatically/manually.
So why did we still need keyed state and operator state.


Thanks





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Arvid Heise | Senior Java Developer




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