I changed it to Tuple2 and that problem is solved.
Any thoughts on this message....
*Unapplied methods are only converted to functions when a function type is
expected.*
*You can make this conversion explicit by writing `updateAcrossEvents _` or
`updateAcrossEvents(_,_,_,_,_)` instead of `updateAcrossEvents`.
.mapGroupsWithState(GroupStateTimeout.EventTimeTimeout())(updateAcrossEvents)*
On Mon, Mar 2, 2020 at 5:12 PM lec ssmi <shicheng31...@gmail.com> wrote:
> maybe you can combine the fields you want to use into one field
>
> Something Something <mailinglist...@gmail.com> 于2020年3月3日周二 上午6:37写道：
>
>> I am writing a Stateful Streaming application in which I am using
>> mapGroupsWithState to create aggregates for Groups but I need to create
>> *Groups
>> based on more than one column in the Input Row*. All the examples in the
>> 'Spark: The Definitive Guide' use only one column such as 'User' or
>> 'Device'. I am using code similar to what's given below. *How do I
>> specify more than one field in the 'groupByKey'?*
>>
>> There are other challenges as well. The book says we can use
>> 'updateAcrossEvents' the way given below but I get compile time error
>> saying:
>>
>>
>> *Error:(43, 65) missing argument list for method updateAcrossEvents in
>> object MainUnapplied methods are only converted to functions when a
>> function type is expected.You can make this conversion explicit by writing
>> `updateAcrossEvents _` or `updateAcrossEvents(_,_,_,_,_)` instead of
>> `updateAcrossEvents`.
>> .mapGroupsWithState(GroupStateTimeout.EventTimeTimeout())(updateAcrossEvents)*
>>
>> Another challenge: Compiler also complains about the my *MyReport*:
>> *Error:(41,
>> 12) Unable to find encoder for type stored in a Dataset. Primitive types
>> (Int, String, etc) and Product types (case classes) are supported by
>> importing spark.implicits._ Support for serializing other types will be
>> added in future releases.*
>>
>> Help in resolving these errors would be greatly appreciated. Thanks in
>> advance.
>>
>>
>> withEventTime
>> .as[MyReport]
>> .groupByKey(_.getKeys.getKey1). // How do I add _.getKeys.getKey2?
>>
>> .mapGroupsWithState(GroupStateTimeout.EventTimeTimeout())(updateAcrossEvents)
>> .writeStream
>> .queryName("test_query")
>> .format("memory")
>> .outputMode("update")
>> .start()
>>
>>
