Hello Michael,
every time you code a Java program you should avoid object creation if
you want an efficient program, because every created object needs to be
garbage collected later (which slows down your program performance).
You can have small Pojos, just try to avoid the call "new" in your
functions:
Instead of:
class Mapper implements MapFunction<String,Pojo> {
public Pojo map(String s) {
Pojo p = new Pojo();
p.f = s;
}
}
do:
class Mapper implements MapFunction<String,Pojo> {
private Pojo p = new Pojo();
public Pojo map(String s) {
p.f = s;
}
}
Then an object is only created once per Mapper and not per record.
Hope this helps.
Regards,
Timo
On 12.08.2015 11:53, Michael Huelfenhaus wrote:
Hello
I have a question about the programming of user defined functions, is it still
like in old Stratosphere times the case that object creation should be avoided
al all cost? Because in some of the examples there are now Tuples and other
objects created before returning them.
I gonna have an at least 6 step streaming plan and I am going to use Pojos. Is
it performance wise a big improvement to define one big pojo that can be used
by all the steps or better to have smaller ones to send less data but create
more objects.
Thanks
Michael
