[ https://issues.apache.org/jira/browse/FLINK-4804?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Chesnay Schepler reassigned FLINK-4804: --------------------------------------- Assignee: Chesnay Schepler > Grouping.first() function usage fails > ------------------------------------- > > Key: FLINK-4804 > URL: https://issues.apache.org/jira/browse/FLINK-4804 > Project: Flink > Issue Type: Bug > Reporter: Yakov Goldberg > Assignee: Chesnay Schepler > > Trying to use Grouping.first() in following example: > {code} > dd2 = env.from_elements((1, "data"), (1, "hello"), (1, "z")) > dd2 \ > .group_by(0) \ > .sort_group(1, Order.ASCENDING) \ > .first(2) \ > .reduce_group(PlainReduce(), combinable=True) > {code} > 1. Is this example correct? > 2. If so, got the following error: > {code} > ------------------------------------------------------------ > The program finished with the following exception: > org.apache.flink.client.program.ProgramInvocationException: The main method > caused an error. > at > org.apache.flink.client.program.PackagedProgram.callMainMethod(PackagedProgram.java:520) > at > org.apache.flink.client.program.PackagedProgram.invokeInteractiveModeForExecution(PackagedProgram.java:403) > at org.apache.flink.client.program.Client.runBlocking(Client.java:248) > at > org.apache.flink.client.CliFrontend.executeProgramBlocking(CliFrontend.java:866) > at org.apache.flink.client.CliFrontend.run(CliFrontend.java:333) > at > org.apache.flink.client.CliFrontend.parseParameters(CliFrontend.java:1192) > at org.apache.flink.client.CliFrontend.main(CliFrontend.java:1243) > Caused by: java.lang.ClassCastException: > org.apache.flink.api.java.operators.SortedGrouping cannot be cast to > org.apache.flink.api.java.DataSet > at > org.apache.flink.python.api.PythonPlanBinder.createFirstOperation(PythonPlanBinder.java:470) > at > org.apache.flink.python.api.PythonPlanBinder.receiveOperations(PythonPlanBinder.java:325) > at > org.apache.flink.python.api.PythonPlanBinder.receivePlan(PythonPlanBinder.java:236) > at > org.apache.flink.python.api.PythonPlanBinder.runPlan(PythonPlanBinder.java:140) > at > org.apache.flink.python.api.PythonPlanBinder.main(PythonPlanBinder.java:113) > at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) > at > sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) > at > sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) > at java.lang.reflect.Method.invoke(Method.java:606) > at > org.apache.flink.client.program.PackagedProgram.callMainMethod(PackagedProgram.java:505) > {code} -- This message was sent by Atlassian JIRA (v6.3.4#6332)