Thanks for your replies.
When I use no state-relevant code in my program,the checkingpoint can be saved
and resumed.❶
So then why we need Keyed State/Operator State/Stateful Function?❷
"the operators are reset to the time of the respective checkpoint."
We already have met the requirement:"resume from checkpoint(last state of each
operator which store the result)"❶,
why we still need ❷?
Thanks for your help~!
------------------ 原始邮件 ------------------
发件人:
"Arvid Heise"
<ar...@ververica.com>;
发送时间: 2020年10月12日(星期一) 下午2:53
收件人: "大森林"<appleyu...@foxmail.com>;
抄送: "Shengkai Fang"<fskm...@gmail.com>;"user"<user@flink.apache.org>;
主题: Re: why we need keyed state and operate state when we already have
checkpoint?
Hi 大森林,
You can always resume from checkpoints independent of the usage of keyed or
non-keyed state of operators.
1 checkpoint contains the state of all operators at a given point in time. Each
operator may have keyed state, raw state, or non-keyed state.
As long as you are not changing the operators (too much) before restarting, you
can always restart.
During (automatic) restart of a Flink application, the state of a given
checkpoint is restored to the operators, such that it looks like the operator
never failed. However, the operators are reset to the time of the respective
checkpoint.
I have no clue what you mean with "previous variable temporary result".
On Wed, Oct 7, 2020 at 9:13 AM 大森林 <appleyu...@foxmail.com> wrote:
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.
------------------ 原始邮件 ------------------
发件人:
"Arvid Heise"
<ar...@ververica.com>;
发送时间: 2020年10月7日(星期三) 下午2:25
收件人: "大森林"<appleyu...@foxmail.com>;
抄送: "Shengkai Fang"<fskm...@gmail.com>;"user"<user@flink.apache.org>;
主题: 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] 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 大森林 <appleyu...@foxmail.com> 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?
------------------ 原始邮件 ------------------
发件人:
"Shengkai Fang"
<fskm...@gmail.com>;
发送时间: 2020年10月7日(星期三) 中午12:43
收件人: "大森林"<appleyu...@foxmail.com>;
抄送: "user"<user@flink.apache.org>;
主题: 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.
大森林 <appleyu...@foxmail.com> 于2020年10月7日周三 下午12:26写道：
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
--
Arvid Heise | Senior Java Developer
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Ververica GmbH
Registered at Amtsgericht Charlottenburg: HRB 158244 B
Managing Directors: Timothy Alexander Steinert, Yip Park Tung Jason, Ji (Toni)
Cheng
--
Arvid Heise | Senior Java Developer
Follow us @VervericaData
--
Join Flink Forward - The Apache Flink Conference
Stream Processing | Event Driven | Real Time
--
Ververica GmbH | Invalidenstrasse 115, 10115 Berlin, Germany
--
Ververica GmbH
Registered at Amtsgericht Charlottenburg: HRB 158244 B
Managing Directors: Timothy Alexander Steinert, Yip Park Tung Jason, Ji (Toni)
Cheng
