Hi Congxian:
For my application i see many uuids under the chk-6 directory ( I posted one in
the sample above). I am trying to understand that if I restart the
application with this checkpoint (which I believe I can just like a savepoint -
I am using chk-6 as an example below)1. I believe each chk-<d> - is a complete
state of checkpoint. Is that correct ?2. How to I point it to the checkpoint
(chk-6) when I submit the job - Do I point it to the jobid or the chk-6
directory ? I am presuming the latter (ie, pointing to the chk06 directory but
just want to confirm.3. Secondly, how does the application map the the files
under the chk-6 to restore the state of each of the stateful operators ?4. Is
there any API by which I can examine the contents of the files under the chk-6
directory ?
Thanks for your help.
Mans
On Wednesday, November 20, 2019, 09:13:39 PM EST, Congxian Qiu
<[email protected]> wrote:
Hi
Currently, the last part (uuid a4d87cda-2afd-47d4-8d3f-b0658466fb2d) is
generated by UUID.randomUUID(), so there is not a easy way to map this to the
assigned in the application.In another word, the last part (uuid
a4d87cda-2afd-47d4-8d3f-b0658466fb2d) belongs to one checkpoint, and the
assigned in the application belongs to one operator, they are different.
Best,Congxian
M Singh <[email protected]> 于2019年11月21日周四 上午6:18写道：
Hi Arvid:
Thanks for your clarification.
I am giving supplying uid for the stateful operators and find the following
directory structure on in the chkpoint directory:
f4e78cb47f9dc12859558be7d15f39d0/chk-6/a4d87cda-2afd-47d4-8d3f-b0658466fb2d
The first part f4e78cb47f9dc12859558be7d15f39d0 is the job_idIs there a way to
map the last part (uuid a4d87cda-2afd-47d4-8d3f-b0658466fb2d) - to the uid
assigned in the application ?
Thanks
On Wednesday, November 20, 2019, 07:52:49 AM EST, Arvid Heise
<[email protected]> wrote:
Hi Mans,
just to follow up. There are no limitations for name or uuid.
The uuid will be in fact hashed internally while the StreamGraph is being
generated, so all characters are allowed.The name is only for debugging
purposes and web ui. If you use very special characters, you may see oddities
in logs/web ui, but nothing should break.
Spaces or parentheses should work in any case.
Best,
Arvid
On Sat, Nov 16, 2019 at 6:40 PM M Singh <[email protected]> wrote:
Thanks Jiayi for your response. I am thinking on the same lines.
Regarding using the same name and uuid, I believe the checkpoint state for an
operator will be easy to identify if the uuid is the same as name. But I am
not sure if having a very long name and uuid or a character like parenthesis,
etc might cause any issues, so just wanted to check.
Mans
On Saturday, November 16, 2019, 11:19:08 AM EST, Jiayi Liao
<[email protected]> wrote:
Hi Mans!
Firstly let’s see how operator’s name and uid is used. AFAIK, operator’s name
is used in WebUI and metrics reporting, and uid is used to mark the uniqueness
of operator which is useful when you’re using state[1].
> Are there any restrictions on the length of the name and uuid attributes?
It’s pretty much the same as you define a string value, so there is no special
restrictions on this.
> Are there any restrictions on the characters used for name and uuid (blank
>spaces, etc) ?
I’m not a hundred percent sure about this but I run a testing program and it
works fine.
> Can the name and uuid be the same ?
Yes. But uuids accross operators cannot be same.
For me I usually set name and uuid for almost every operator, which gives me
better experience in monitoring and scaling.
Hope this helps.
[1]
https://ci.apache.org/projects/flink/flink-docs-stable/ops/upgrading.html#matching-operator-state
Best,
Jiayi Liao
At 2019-11-16 18:35:38, "M Singh" <[email protected]> wrote:
Hi:
I am working on a project and wanted to find out what are the best practices
for setting name and uuid for operators:
1. Are there any restrictions on the length of the name and uuid attributes ?2.
Are there any restrictions on the characters used for name and uuid (blank
spaces, etc) ?3. Can the name and uuid be the same ?
Please let me know if there is any other advice.
Thanks
Mans
