查询firebase用户名

Question

我正在尝试从firebase查询用户名，它没有获取查询，我得到这个日志有没有人知道这意味着什么？

  

使用未指定的索引。考虑添加“.indexOn”：   / contacts / users对您的安全性的“contacts / t25ha71bw0gRIU9HRhY2ecGSAS03”   提高绩效的规则

Firebase规则

{
  "rules": {
    ".read": "(auth != null)",
    ".write": "(auth != null)",
    "location":{
      "$uid": {
        ".indexOn": ["lat","long"] 
      }
    },
    "events": {
      "$uid": {
        ".read": "(auth != null) && !data.child('deleted').exists()",
        ".write": "(auth != null)",
        ".indexOn": ["name", "owner"]
      }
    },
    "groups": {
      "$uid": {
        ".read": "(auth != null) && !data.child('deleted').exists()",
        ".indexOn": ["name", "members", "owner"]
      }
    },
    "users": {
      "$uid": {
        ".read": "(auth != null) && !data.child('deleted').exists()",
        "contacts" : {
          ".indexOn": ".value"
        },
        ".indexOn": ["username"]
      }
    }
  }
}

搜索查询

   func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String)     {
    updateSearchResult(text: searchText)
    guard !searchText.isEmpty else { return }

    DispatchQueue.global(qos: .userInteractive).asyncAfter(deadline: DispatchTime.now() + .seconds(1)) {
        if self.contactType == .contact {
            AppFirRef.userRef.queryOrdered(byChild:"username")
                .queryStarting(atValue: searchText)
                .queryEnding(atValue: searchText+"\\uf8ff")
                .observeSingleEvent(of: .value, with: { (snapshot) in
                var contacts = Set<LAContact>()
                for case let snap as FIRDataSnapshot in snapshot.children {
                    guard let value = snap.value as? [String : Any] else { continue }
                    let item = LAContact(value: value)
                    contacts.insert(item)
                }
                let filteredItems = self.filteredItems as! [LAContact]
                let filtereSet = contacts.union(filteredItems)
                self.filteredItems = Array(filtereSet)
                self.tableView.reloadData()
            })
        }
    }
}

AppFirRef

final class AppFirRef {
static let baseRef = FIRDatabase.database().reference()
    static var currentUserRef: FIRDatabaseReference! {
        guard let user = FIRAuth.auth()?.currentUser else { return nil }
        return userRef.child(user.uid)
    }
    static var userRef = baseRef.child("users")
    static var eventRef = baseRef.child("events")
    static var groupRef = baseRef.child("groups")
    static var messageRef = baseRef.child("messages")
}