使用set（）方法更新数据的效率怀疑

Question

i know very well how the set method work. but I have a doubt about its use to update a node. I want to know if when I save an object with a new field (so the same values as before + a new field), is all the fields of the object uploaded again or is only the new field loaded?

I see that in the database the unchanged fields are not lit green during writing, this makes me think that

1) all object is sent to the database and after the upload the database simply ignores the fields without modifications.

2) the unchanged fields are not even uploaded into the database (they simply stay in the client) but only new fields are sent.

in the second case in a context of large objects there would be a considerable saving of bandwidth

const object = {
  name: 'tower10',
  type: 'building',
  rooms: 10
};

await db.ref('object/1').set(object);
object.extra = 'extra content';
object.extra1 = 'extra content 1';
await db.ref('object/1').set(object);

Answer 1

The entire object is sent with every call to set() . Children whose values are not change don't count as updates for listeners (as you noticed in the console when their values don't flash). If you know only certain values are going to change, you cloud only update with those values and not send the entire thing. But the object you're showing here is rather small, and I don't think optimizing this small object will matter very much.