The only thing you need to be aware of (in the batch API) is that you
cannot simply gather elements in a list any more.
The following does not work when enabling object reuse:
class MyReducer implements GroupReduceFunction<In, Out> {
public void reduceGroup(Iterable<In> values, Collector<Out> out) {
List<In> allValues = new List<In>();
for (In i : values) {
allValues.add(i);
}
}
}
In general, object reuse is a feature that makes sense if you want to
optimize GC performance. If you don't need it, all the better. It is fairly
easy to accidentally implement the user functions to hold onto reused
object references, and compute wrong results that way.
Greetings,
Stephan
On Tue, Feb 9, 2016 at 10:48 AM, Till Rohrmann <trohrm...@apache.org> wrote:
> Yes, you're right Arnaud.
>
> Cheers,
> Till
>
> On Tue, Feb 9, 2016 at 10:42 AM, LINZ, Arnaud <al...@bouyguestelecom.fr>
> wrote:
>
>> Hi,
>>
>>
>>
>> I just want to be sure : when I set enableObjectReuse, I don’t need to
>> create copies of objects that I get as input and return as output but which
>> I don’t keep inside my user function ?
>>
>> For instance, if I want to join Tuple2(A,B) with C into Tuple3(A,B,C)
>> using a Join function, I can write something like :
>>
>>
>>
>> public Tuple3 join(Tuple2 first, Object second) {
>>
>> return Tuple3.of(first.f0, first.f1, second);
>>
>> }
>>
>> And not return Tuple3.of(first.f0.clone(),
>> first.f1.clone(), second.clone()) ?
>>
>>
>>
>>
>>
>> Best regards,
>>
>> Arnaud
>>
>>
>>
>>
>>
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