Hi Guobao, I just re-checked the data stream API. There is an interesting restriction of `AggregateFunction`. It could not be a rich function. And there are already several relevant issues [1][2][3]. I guess your scenario might be relevant to this restriction (I assume you are using table/SQL API).
The bad news is none of these issues are implemented. I didn't find a workaround way to access metric group in data stream API. I'm not sure it could be done in table/SQL or not. [1] https://issues.apache.org/jira/browse/FLINK-14275 [2] https://issues.apache.org/jira/browse/FLINK-5094 [3] https://issues.apache.org/jira/browse/FLINK-11198 Thanks, Biao /'bɪ.aʊ/ On Wed, 4 Dec 2019 at 11:23, Jingsong Li <jingsongl...@gmail.com> wrote: > Hi Guobao, > > Looks like this is from table/SQL API. > You can override public void open(FunctionContext context) > It should work, can you provide more information? Like: > - version > - which planner > - what problem, open method never being invoked? > > Best, > Jingsong Lee > > On Wed, Dec 4, 2019 at 11:09 AM Biao Liu <mmyy1...@gmail.com> wrote: > >> Hi Guobao, >> >> Are you using table API? I'm not familiar with table API, but for data >> stream API, generally speaking user could do some initialization through >> "open" method of "Rich" function, like "RichAggregateFunction". >> >> Thanks, >> Biao /'bɪ.aʊ/ >> >> >> >> On Tue, 3 Dec 2019 at 22:44, Guobao Li <gu...@criteo.com> wrote: >> >>> Hi community, >>> >>> >>> >>> I am trying to register a metric in an aggregate UDF by overriding the >>> *open* function. According to the documentation, the *open* function >>> can be override in order to retrieve the metric group to do the metric >>> registration. But it works only on ScalarFunction not on AggregateFunction. >>> Since the *open* function is not invoked by AggregateFunction. Could >>> anyone help me out of it? >>> >>> >>> >>> Thanks, >>> >>> Guobao >>> >>> >>> >> > > -- > Best, Jingsong Lee >
