CODEWITHSUNDEEP
androidfirebasefirebase-realtime-database
Sreekanth Karumanaghat
Sreekanth Karumanaghat

Reputation: 3403

Firebase listeners first time invocation takes time

First time listener firing takes so much time (approx. 40s), subsequent loads takes lesser time (approx. 1s), how can speed up the first time load as well?

I have given,

    FirebaseDatabase.getInstance().setPersistenceEnabled(true);

on start of the activity.

        DatabaseReference ref = FirebaseDatabase.getInstance().getReference("");
        ref.keepSynced(true);
        ref.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {


            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });

Upvotes: 1

Views: 1669

Answers (1)

Alex Mamo
Alex Mamo

Reputation: 138824

If you are using a listener, you need to know that you are trying to read data over the internet. You cannot compare this with an atempt to read a SQLite database, which is stored locally on disk. The speed of getting the data from Firebase servers, depends on the speed of your internet connection and on the ammount of data that you are trying to get. So most likely the reason for waiting so much is one of this. If the reason is the ammount of data, try to optimize your queries or try to get the data in small parts.

If we are speaking abot the first atempt to read a record, it might be slower than the subsequent ones, because it has to initiate the internet connection. I know that Firebase team is trying to improve the performance, but you can't expect 0ms when retrieving data over a network.

According to your comment, I need to tell you a few more things. There is no way to force the retrieval of the data from the cache while you're connected to the server, as you cannot to stop the retrieval of the data from the cache while you are not connected to the server.

Firebase is desinged to retrieve data from the chache when the device is permanently offline or while your application temporarily loses its network connection and you cannot change this behaviour.

Edit:

So to get the FirebaseDatabase object you need to use the following line of code once:

FirebaseDatabase firebaseDatabase = FirebaseDatabase.getInstance();

Then to get a DatabaseReference, you need to use the following line.

DatabaseReference rootRef = firebaseDatabase.getReference();

I'm sure you'll need to in your activity more then one reference. Let's say you'll use two:

DatabaseReference usersRef = rootRef.child("users");
DatabaseReference postRef = rootRef.child("post");

You can now add a listener for on each one of these references like this:

ValueEventListener eventListener = new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        //code to get the data
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {}
};
usersRef.addListenerForSingleValueEvent(eventListener);

And the code the remove the listener is as explained in my answer from this post.

Don't forget, onDestroy() is not always called.

As a conclusion, you create a single database connection, use as many references you need, add the listeners accordingly, remove then according to the life-cycle of you activity.

Upvotes: 3

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