Re: Strange behavior on filter, group and reduce DataSets

Posted by Fabian Hueske-2 on
URL: http://deprecated-apache-flink-user-mailing-list-archive.369.s1.nabble.com/ANNOUNCE-Apache-Flink-1-3-3-released-tp18942p19009.html

Ah, thanks for the update!

I'll have a look at that.

2018-03-19 15:13 GMT+01:00 Fabian Hueske <[hidden email]>:

HI Simone,

Looking at the plan, I don't see why this should be happening. The pseudo code looks fine as well.

Any chance that you can create a minimal program to reproduce the problem?

Thanks,

Fabian

2018-03-19 12:04 GMT+01:00 simone <[hidden email]>:

Hi Fabian,

reuse is not enabled. I attach the plan of the execution.

Thanks,
Simone

On 19/03/2018 11:36, Fabian Hueske wrote:

Hi,

Union is actually a very simple operator (not even an operator in Flink terms). It just merges to inputs. There is no additional logic involved.

Therefore, it should also not emit records before either of both ReduceFunctions sorted its data.
Once the data has been sorted for the ReduceFunction, the data is reduced and emitted in a pipelined fashion, i.e., once the first record is reduced, it is forwarded into the MapFunction (passing the unioned inputs).

So it is not unexpected that Map starts processing before the ReduceFunction terminated.

Did you enable object reuse [1]?

If yes, try to disable it. If you want to reuse objects, you have to be careful in how you implement your functions.

If no, can you share the plan (ExecutionEnvironment.getExecutionPlan()) that was generated for the program?

Thanks,

Fabian

[1] https://ci.apache.org/projects/flink/flink-docs-release-1.3/dev/batch/index.html#operating-on-data-objects-in-functions

2018-03-19 9:51 GMT+01:00 Flavio Pompermaier <[hidden email]>:

Any help on this? This thing is very strange..the "manual" union of the output of the 2 datasets is different than the flink-union of them..

Could it be a problem of the flink optimizer?

Best,

Flavio

On Fri, Mar 16, 2018 at 4:01 PM, simone <[hidden email]> wrote:

Sorry, I translated the code into pseudocode too fast. That is indeed an equals.

On 16/03/2018 15:58, Kien Truong wrote:

Hi,

Just a guest, but string compare in Java should be using equals method, not == operator.

Regards,

Kien

On 3/16/2018 9:47 PM, simone wrote:

subject.getField("field1") == "";