DbException: Could not renew tx (another read transaction is still active on this thread) (error code -30783)

[fakerqu]

Issue Basics

• ObjectBox version: 2.3.4
• Reproducibility: occasionally without visible pattern

Reproducing the bug

Description

I'm now using objectbox with multi-modules, before using objectbox on my library-module it works fine, but recently the error occours in different occasions with same exceptions below.

Code

    @Override
    protected void onResume() {
        if (GlobalVariables.bUserInfoUpdateFlag || ObjectBoxManager.getInstance().getUserEntityBox().isEmpty()) {
            loadingUerInfo();
        } else {
            reBuildFirstItem();
        }
        this.myInfoListAdapter.notifyDataSetChanged();
        super.onResume();
    }

Logs & stackstraces

2019-09-10 13:47:47.958 6866-6866/com.masstest E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.masstest, PID: 6866
    java.lang.RuntimeException: Unable to resume activity {com.masstest/com.masstest.activity.MyInfoManagerActivity}: io.objectbox.exception.DbException: Could not renew tx (another read transaction is still active on this thread) (error code -30783)
        at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3974)
        at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:188)
        at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:348)
        at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:774)
        at android.widget.TabHost.setCurrentTab(TabHost.java:428)
        at android.widget.TabHost.setCurrentTabByTag(TabHost.java:309)
        at com.masstest.activity.MainTabWidgetActivity$1.onCheckedChanged(MainTabWidgetActivity.java:146)
        at android.widget.RadioGroup.setCheckedId(RadioGroup.java:190)
        at android.widget.RadioGroup.access$600(RadioGroup.java:57)
        at android.widget.RadioGroup$CheckedStateTracker.onCheckedChanged(RadioGroup.java:375)
        at android.widget.CompoundButton.setChecked(CompoundButton.java:174)
        at android.widget.CompoundButton.toggle(CompoundButton.java:127)
        at android.widget.RadioButton.toggle(RadioButton.java:76)
        at android.widget.CompoundButton.performClick(CompoundButton.java:132)
        at android.view.View.performClickInternal(View.java:6574)
        at android.view.View.access$3100(View.java:778)
        at android.view.View$PerformClick.run(View.java:25889)
        at android.os.Handler.handleCallback(Handler.java:873)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:192)
        at android.app.ActivityThread.main(ActivityThread.java:7116)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:532)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:867)
     Caused by: io.objectbox.exception.DbException: Could not renew tx (another read transaction is still active on this thread) (error code -30783)
        at io.objectbox.Transaction.nativeRenew(Native Method)
        at io.objectbox.Transaction.renew(Transaction.java:153)
        at io.objectbox.Box.getReader(Box.java:78)
        at io.objectbox.Box.count(Box.java:288)
        at io.objectbox.Box.isEmpty(Box.java:298)
        at com.masstest.activity.MyInfoManagerActivity.onResume(MyInfoManagerActivity.java:183)
        at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1413)
        at android.app.Activity.performResume(Activity.java:7422)
        at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3964)
        at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:188) 
        at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:348) 
        at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:774) 
        at android.widget.TabHost.setCurrentTab(TabHost.java:428) 
        at android.widget.TabHost.setCurrentTabByTag(TabHost.java:309) 
        at com.masstest.activity.MainTabWidgetActivity$1.onCheckedChanged(MainTabWidgetActivity.java:146) 
        at android.widget.RadioGroup.setCheckedId(RadioGroup.java:190) 
        at android.widget.RadioGroup.access$600(RadioGroup.java:57) 
        at android.widget.RadioGroup$CheckedStateTracker.onCheckedChanged(RadioGroup.java:375) 
        at android.widget.CompoundButton.setChecked(CompoundButton.java:174) 
        at android.widget.CompoundButton.toggle(CompoundButton.java:127) 
        at android.widget.RadioButton.toggle(RadioButton.java:76) 
        at android.widget.CompoundButton.performClick(CompoundButton.java:132) 
        at android.view.View.performClickInternal(View.java:6574) 
        at android.view.View.access$3100(View.java:778) 
        at android.view.View$PerformClick.run(View.java:25889) 
        at android.os.Handler.handleCallback(Handler.java:873) 
        at android.os.Handler.dispatchMessage(Handler.java:99) 
        at android.os.Looper.loop(Looper.java:192) 
        at android.app.ActivityThread.main(ActivityThread.java:7116) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:532) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:867) 

Entities

It seems have no relationship with my entities

[greenrobot-team]

Thanks for reporting. Could not renew tx (another read transaction is still active on this thread) means that somewhere else within the app an ObjectBox operation is still running/could not be cleaned up properly on, in your case, the main thread.

Is it possible that an ObjectBox operation on the main thread might get interrupted within your app?

Without looking at the code I can't really say if there is an issue. Do you have a minimal example project that can somewhat reliably reproduce this?

Edit: also check if you are using some obfuscation/security hardening tool that might modify (and hence break) ObjectBox code. #432

[fakerqu]

Problem solved, copying objectbox's **.mdb file and trying to edit boxstore at the same time will cause this exception. Is there any method backing up my boxstore?
Thank you!

[greenrobot-team]

Is there any method backing up my boxstore?

Nothing official. It's probably better to export/import a standard format like JSON anyhow.

If you really must copy the database file, make sure to close() the BoxStore first after all operations have finished. See details at
http://objectbox.io/files/objectbox-java/current/io/objectbox/BoxStore.html#close--