When I tried to calculate the median of the age field in a table with 120
million rows, I implemented a custom UDAF. However, there was a significant
performance difference between the two different types of accumulator. The
ListView stated that it would enable the state backend when encountering
large amounts of data. How can I observe this process and which classes are
responsible for these functions?
```java
public static class State implements Serializable {
public int scale = 2;
@DataTypeHint(value = "ARRAY<DOUBLE>")
public ArrayList<Double> numbers;
public State() {}
}
@Override
public State createAccumulator() {
State state = new State();
state.numbers = new ArrayList<>();
return state;
}
```java
public static class State implements Serializable {
public int scale = 2;
public ListView<Double> numbers;
public State() {}
}
@Override
public State createAccumulator() {
State state = new State();
state.numbers = new ListView<>();
return state;
}
