IssueTracker

For one of observables (single, maybe) we don't specify a subscvription thread so that developer can control where the action happens.
For flowables / observables; we always use the Room IO thread fo rthe actual query since we may repeat the work.

For LiveData, ti si always the Room IO Thread.

Until we can extend Room Query methods to receive non-query parameter (e.g. a Scheduler) we cannot do this.
At least room catches this instantly since it will crash w/ db access on main thread exception.

Hello Yigit, nice to meet you here! :)
Probably I should have described the problem more clearly.

I'm using Flowable, and hopefully it executes queries in background thread (at least, app does not crash with IllegalStateException, as with Single).

But nevertheless subscribing and disposing(!) does cause StrictMode violations. Stack trace examples:

D/StrictMode: StrictMode policy violation; ~duration=17 ms: android.os.StrictMode$StrictModeDiskWriteViolation: policy=31 violation=1
        at android.os.StrictMode$AndroidBlockGuardPolicy.onWriteToDisk(StrictMode.java:1111)
        at android.database.sqlite.SQLiteConnection.applyBlockGuardPolicy(SQLiteConnection.java:1043)
        at android.database.sqlite.SQLiteConnection.execute(SQLiteConnection.java:552)
        at android.database.sqlite.SQLiteSession.beginTransactionUnchecked(SQLiteSession.java:323)
        at android.database.sqlite.SQLiteSession.beginTransaction(SQLiteSession.java:298)
        at android.database.sqlite.SQLiteDatabase.beginTransaction(SQLiteDatabase.java:505)
        at android.database.sqlite.SQLiteDatabase.beginTransaction(SQLiteDatabase.java:416)
        at androidx.sqlite.db.framework.FrameworkSQLiteDatabase.beginTransaction(FrameworkSQLiteDatabase.java:69)
        at androidx.room.InvalidationTracker.syncTriggers(InvalidationTracker.java:426)
        at androidx.room.InvalidationTracker.syncTriggers(InvalidationTracker.java:465)
        at androidx.room.InvalidationTracker.addObserver(InvalidationTracker.java:249)
        at androidx.room.RxRoom$1.subscribe(RxRoom.java:79)
        at io.reactivex.internal.operators.flowable.FlowableCreate.subscribeActual(FlowableCreate.java:71)
        at io.reactivex.Flowable.subscribe(Flowable.java:14479)
        at io.reactivex.internal.operators.flowable.FlowableObserveOn.subscribeActual(FlowableObserveOn.java:56)
        at io.reactivex.Flowable.subscribe(Flowable.java:14479)
        at io.reactivex.internal.operators.flowable.FlowableFlatMapMaybe.subscribeActual(FlowableFlatMapMaybe.java:54)
        at io.reactivex.Flowable.subscribe(Flowable.java:14479)
        at io.reactivex.Flowable.subscribe(Flowable.java:14416)
        at io.reactivex.Flowable.subscribe(Flowable.java:14306)
        at gmk57.strictroom.MainActivity.onCreate(MainActivity.java:30)

StrictMode policy violation; ~duration=108 ms: android.os.StrictMode$StrictModeDiskWriteViolation: policy=31 violation=1
        at android.os.StrictMode$AndroidBlockGuardPolicy.onWriteToDisk(StrictMode.java:1111)
        at android.database.sqlite.SQLiteConnection.applyBlockGuardPolicy(SQLiteConnection.java:1043)
        at android.database.sqlite.SQLiteConnection.execute(SQLiteConnection.java:552)
        at android.database.sqlite.SQLiteSession.beginTransactionUnchecked(SQLiteSession.java:323)
        at android.database.sqlite.SQLiteSession.beginTransaction(SQLiteSession.java:298)
        at android.database.sqlite.SQLiteDatabase.beginTransaction(SQLiteDatabase.java:505)
        at android.database.sqlite.SQLiteDatabase.beginTransaction(SQLiteDatabase.java:416)
        at androidx.sqlite.db.framework.FrameworkSQLiteDatabase.beginTransaction(FrameworkSQLiteDatabase.java:69)
        at androidx.room.InvalidationTracker.syncTriggers(InvalidationTracker.java:426)
        at androidx.room.InvalidationTracker.syncTriggers(InvalidationTracker.java:465)
        at androidx.room.InvalidationTracker.removeObserver(InvalidationTracker.java:281)
        at androidx.room.RxRoom$1$2.run(RxRoom.java:83)
        at io.reactivex.disposables.ActionDisposable.onDisposed(ActionDisposable.java:30)
        at io.reactivex.disposables.ActionDisposable.onDisposed(ActionDisposable.java:19)
        at io.reactivex.disposables.ReferenceDisposable.dispose(ReferenceDisposable.java:43)
        at io.reactivex.internal.disposables.DisposableHelper.dispose(DisposableHelper.java:124)
        at io.reactivex.internal.disposables.SequentialDisposable.dispose(SequentialDisposable.java:72)
        at io.reactivex.internal.operators.flowable.FlowableCreate$BaseEmitter.cancel(FlowableCreate.java:301)
        at io.reactivex.internal.operators.flowable.FlowableObserveOn$BaseObserveOnSubscriber.cancel(FlowableObserveOn.java:154)
        at io.reactivex.internal.operators.flowable.FlowableFlatMapMaybe$FlatMapMaybeSubscriber.cancel(FlowableFlatMapMaybe.java:158)
        at io.reactivex.internal.subscriptions.SubscriptionHelper.cancel(SubscriptionHelper.java:189)
        at io.reactivex.internal.subscribers.LambdaSubscriber.cancel(LambdaSubscriber.java:119)
        at io.reactivex.internal.subscribers.LambdaSubscriber.dispose(LambdaSubscriber.java:104)
        at gmk57.strictroom.MainActivity.onDestroy(MainActivity.java:37)