Android app freezes with 100K objects dataset

Goal

I’m thinking of building an Android app using Realm.

Over time, its dataset could grow to become huge. So, to make sure I could work with Realm, I have built a simple test project with it.

My goal is to have multiple feeds to filter and group items.

Code (Kotlin)

Here are my test objects:

open class Feed(
        @PrimaryKey
        open var id: Long = 0,

        open var name: String? = "feed$id"
) : RealmObject()

open class Item(
        @PrimaryKey
        open var id: Long = 0,

        open var name: String = "item$id",

        open var feed: Feed? = null
) : RealmObject()

I have a RecyclerView.Adapter that receives a list of items RealmResults<Item> object. Here’s the query:

fun Realm.getItems(feedId: Long): RealmResults<Item> =
        where(Item::class.java)
                .equalTo("feed.id", feedId)
                .findAllSorted("id", Sort.DESCENDING)

Test

My test project dataset:

• 1 Feed
• 100K+ Item objects

Issue

Whenever a new Item is created, the UI freezes for 3 to 5 seconds.

If I remove the sorting on the query, the freeze is not so long, but it still breaks. Also, my dataset will be a lot more complex and 100K is just a reference number.

Skipped 159 frames!  The application may be doing too much work on its main thread.
Window 'Window{2850f572 u0 io.test/io.test.activity.MainActivity}' spent 5048.6ms processing the last input event: MotionEvent(…)

Debug

With some method profiling, I noticed that io.realm.internal.TableView.nativeSyncIfNeeded() is the culprit. It is too slow, and it runs in the UI thread.

Question

Is there any optimization I could do to handle a dataset of this size? Thanks.

Version of Realm

Realm version: 1.2.0

[nhachicha]

Hi @jpsim suggestion, have you tried async queries it call https://github.com/realm/realm-java/blob/master/realm/realm-library/src/main/java/io/realm/RealmResults.java#L909 on completion that will not invoke nativeSyncIfNeeded Cheers

[Zhuinden]

@jpmcosta if there is one thing you could try, it’s RealmRecycleViewAdapter from https://github.com/realm/realm-android-adapters and findAllAsync()?