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Posted to user@flink.apache.org by M Singh <ma...@yahoo.com> on 2019/11/16 11:35:38 UTC

Apache Flink - Operator name and uuid best practices

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

Re: Re:Apache Flink - Operator name and uuid best practices

Posted by M Singh <ma...@yahoo.com>.

Thanks so much Congxian for your pointers - I will try to go through them. Mans
On Thursday, November 21, 2019, 07:26:49 AM EST, Congxian Qiu <qc...@gmail.com> wrote:

Hi1. I think this issue[1] can help to understand the directory layout2. chk-6 directory or the metafilePath, for more information, you can ref to[2][3]3. every checkpoint contains a meta-file record such, maybe you can ref to[4], and debug it for more information4. currently, you need to go through the restore logic to see if the files' contents
[1] https://issues.apache.org/jira/browse/FLINK-8531[2] https://github.com/apache/flink/blob/master/flink-runtime/src/main/java/org/apache/flink/runtime/checkpoint/CheckpointCoordinator.java#L1153[3] https://ci.apache.org/projects/flink/flink-docs-release-1.9/ops/state/checkpoints.html#resuming-from-a-retained-checkpoint[4] https://github.com/apache/flink/blob/master/flink-runtime/src/test/java/org/apache/flink/runtime/checkpoint/CheckpointMetadataLoadingTest.java
Best,Congxian

M Singh <ma...@yahoo.com> 于2019年11月21日周四 下午7:44写道：

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 <qc...@gmail.com> 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 <ma...@yahoo.com> 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 <ar...@ververica.com> 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 <ma...@yahoo.com> 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 <bu...@163.com> 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" <ma...@yahoo.com> 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

Re: Re:Apache Flink - Operator name and uuid best practices

Posted by Congxian Qiu <qc...@gmail.com>.

Hi
1. I think this issue[1] can help to understand the directory layout
2. chk-6 directory or the metafilePath, for more information, you can ref
to[2][3]
3. every checkpoint contains a meta-file record such, maybe you can ref
to[4], and debug it for more information
4. currently, you need to go through  the restore logic to see if the
files' contents

[1] https://issues.apache.org/jira/browse/FLINK-8531
[2]
https://github.com/apache/flink/blob/master/flink-runtime/src/main/java/org/apache/flink/runtime/checkpoint/CheckpointCoordinator.java#L1153
[3]
https://ci.apache.org/projects/flink/flink-docs-release-1.9/ops/state/checkpoints.html#resuming-from-a-retained-checkpoint
[4]
https://github.com/apache/flink/blob/master/flink-runtime/src/test/java/org/apache/flink/runtime/checkpoint/CheckpointMetadataLoadingTest.java
Best,
Congxian


M Singh <ma...@yahoo.com> 于2019年11月21日周四 下午7:44写道：

> 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 <
> qcx978132955@gmail.com> 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 <ma...@yahoo.com> 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_id
> Is 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 <
> arvid@ververica.com> 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 <ma...@yahoo.com> 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 <
> bupt_ljy@163.com> 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" <ma...@yahoo.com> 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
>
>
>
>
>
>

Re: Re:Apache Flink - Operator name and uuid best practices

Posted by M Singh <ma...@yahoo.com>.

M Singh <ma...@yahoo.com> 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:

Thanks
On Wednesday, November 20, 2019, 07:52:49 AM EST, Arvid Heise <ar...@ververica.com> wrote:

Hi Mans,
just to follow up. There are no limitations for name or uuid.

Best,
Arvid

On Sat, Nov 16, 2019 at 6:40 PM M Singh <ma...@yahoo.com> wrote:

Hi Mans!

> 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" <ma...@yahoo.com> wrote:

Re: Re:Apache Flink - Operator name and uuid best practices

Posted by Congxian Qiu <qc...@gmail.com>.

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 <ma...@yahoo.com> 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_id
> Is 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 <
> arvid@ververica.com> 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 <ma...@yahoo.com> 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 <
> bupt_ljy@163.com> 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" <ma...@yahoo.com> 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
>
>
>
>
>
>

Re: Re:Apache Flink - Operator name and uuid best practices

Posted by M Singh <ma...@yahoo.com>.

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:

Thanks
On Wednesday, November 20, 2019, 07:52:49 AM EST, Arvid Heise <ar...@ververica.com> wrote:

Hi Mans,
just to follow up. There are no limitations for name or uuid.

Best,
Arvid

On Sat, Nov 16, 2019 at 6:40 PM M Singh <ma...@yahoo.com> wrote:

Hi Mans!

> 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" <ma...@yahoo.com> wrote:

Re: Re:Apache Flink - Operator name and uuid best practices

Posted by M Singh <ma...@yahoo.com>.

Hi Mans!

> 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" <ma...@yahoo.com> wrote:

Re:Apache Flink - Operator name and uuid best practices

Posted by Jiayi Liao <bu...@163.com>.

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" <ma...@yahoo.com> 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