Remove Attributes combination from onEnd

[wgy035]

Hopefully resolves #11887

Remove reduntant attributes combination in OperationListener.onEnd, move all attributes extract to AttributesExtractor.onEnd

[steverao]

The modification here is useless.

[steverao]

There are some CI failures, you can solve them by referring to https://gradle.com/s/7qpfxdz7iymuy

[laurit]

Only the attributes that are added at the start will be available for sampling. Moving all the attributes to the onEnd will make sampling impossible.

[wgy035]

So I need to figure out which attributes impact sampling, and those attributes are the minimum set need to retain, right?

According to semantic-conventions(e.g. http-spans), I'd like to extract the unique attributes of span at the start without needing to pass them on. The common attributes attributes should be extracted at the end.

[laurit]

Also see #11092

[laurit]

Did you consider using something like

public final class CompositeAttributes implements Attributes {
  private final Attributes first;
  private final Attributes second;

  private CompositeAttributes(Attributes first, Attributes second) {
    this.first = first;
    this.second = second;
  }

  public static Attributes of(Attributes first, Attributes second) {
    return new CompositeAttributes(first, second);
  }

  @Nullable
  @Override
  public <T> T get(AttributeKey<T> attributeKey) {
    T value = first.get(attributeKey);
    if (value != null) {
      return value;
    }
    return second.get(attributeKey);
  }

  @Override
  public void forEach(BiConsumer<? super AttributeKey<?>, ? super Object> biConsumer) {
    first.forEach(biConsumer);
    second.forEach(biConsumer);
  }

  @Override
  public int size() {
    return first.size() + second.size();
  }

  @Override
  public boolean isEmpty() {
    return first.isEmpty() && second.isEmpty();
  }

  @Override
  public Map<AttributeKey<?>, Object> asMap() {
    Map<AttributeKey<?>, Object> map = new HashMap<>();
    map.putAll(first.asMap());
    map.putAll(second.asMap());
    return map;
  }

  @Override
  public AttributesBuilder toBuilder() {
    return first.toBuilder().putAll(second);
  }
}

[laurit]

@wgy035 have you had a chance to check whether composing the start and end attributes as described above would help?

[wgy035]

@wgy035 have you had a chance to check whether composing the start and end attributes as described above would help?

@laurit yep, using such a composite structure will reduce traverse overhead and approximately a CompositeAttributesBuilder is also needed, now I'm testing the performance improvement and the code will be updated with a new commit.