yyanyy commented on pull request #2069:
URL: https://github.com/apache/iceberg/pull/2069#issuecomment-761266457
> Odd, maybe we're trying different things. What does this print for you?
>
> ```
> public class Comp {
> public static void main(String[] args) {
> System.out.println(Double.NaN > 0.0);
> }
> }
> ```
>
> I'm on OpenJDK 1.8, and this prints `false` for me.
Yeah this prints `false` for me too, as well as `Double.NaN == Double.NaN`.
I think we workaround this problem in evaluators by using a
[`Comparator.naturalOrder()`](https://github.com/apache/iceberg/blob/master/api/src/main/java/org/apache/iceberg/expressions/Literals.java#L156)
instead of direct operator comparison, as the following code prints the
behavior that NaN is considered larger than positive infinity as described in
[here](https://docs.oracle.com/javase/8/docs/api/java/lang/Double.html#compareTo-java.lang.Double-)(by
returning -1, 1, 1, -1, 0 respectively)
```
Comparator comparator = Comparator.naturalOrder();
System.out.println(comparator.compare(1.2F, Float.NaN));
System.out.println(comparator.compare(Float.NaN, 1.2F));
System.out.println(comparator.compare(Float.NaN,
Float.POSITIVE_INFINITY));
System.out.println(comparator.compare(Float.POSITIVE_INFINITY,
Float.NaN));
System.out.println(comparator.compare(Float.NaN, Float.NaN));
```
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