Unexpectedly large Realm file size

问题:

This question is about using two different ways to insert objects into a Realm. I noticed that the first method is a lot faster, but the size result is huge comparing with the second method. The diference between the two approaches is moving the write transaction outside vs inside of the for loop.

// Create realm file
let realm = try! Realm(fileURL: banco_url!)

When I add objects like this, the Realm file grows to 75.5MB:

try! realm.write {
    for i in 1...40000 {
        let new_realm_obj = realm_obj(value: ["id" : incrementID(),
                                              "a": "123",
                                              "b": 12.12,
                                              "c": 66,
                                              "d": 13.13,
                                              "e": 0.6,
                                              "f": "01100110",
                                              "g": DateTime,
                                              "h": 3])

        realm.add(new_realm_obj)
        print("