Random data losses on iOS

[graphefruit]

Hey there, my application is using the ionic-storage. I've been reported since 1 week now by multiple users all on iOS that they have encountered random data losses. The application is tracking coffee, and each coffee results into one brew. Users tell me that some of the brews are missing, but strangly not ALL of them.

Funnyly enough I'm myself on iOS and I don't encouter this issue since months.

Also to mention, the code usage to access the database, storage things etc, haven't been change since more then 5 years, and now randomly this issue appears.

Also half year back, I realized that Apple shoot the database where the entries in the Database where corrupted and entries inside the array got corrupted - But this was from Update 17.1 to 17.2 - which I could fix with backups etc.

The storage driver which is used on the users side is logged as:

Storage-Driver: asyncStorage

 IonicStorageModule.forRoot({
      name: '__baristaDB',
      driverOrder: [
        Drivers.IndexedDB,
        CordovaSQLiteDriver._driver,
        Drivers.LocalStorage,
      ],
    }),

Versions:

"@ionic/cli": "^7.1.5",
"@ionic/storage": "^4.0.0",
"@ionic/storage-angular": "^4.0.0",
12.0.0 (cordova-lib@12.0.1)
 "@angular/common": "^16.2.7",
ios 7.0.0

I'd be happy if someone could give me a helping hand here what to try and how to get down to the issues root cause. Thank you so far Lars

[graphefruit]

The issue finally could be reproduced on a user side where I build in logs.

The thrown error is: "Error: Uncaught (in promise): UnknownError: Connection to Indexed Database server lost. Refresh the page to try again",

This error is referencing to this already reported bug: https://bugs.webkit.org/show_bug.cgi?id=197050

Somehow it also tells, that with iOS 17.4.X this issue has been increased much more, because before we didn't have this kind of issue.

I've also opend up a forum-ticket here: https://forums.developer.apple.com/forums/thread/750122?page=1#785564022

[juhrlass]

As this is obviously a problem with the underlying technology (IndexedDB) - What could be the best strategy to mitigate, workaround or fix the problem? Switch the storage Engine to something like this? https://github.com/capacitor-community/sqlite

[graphefruit]

As this is obviously a problem with the underlying technology (IndexedDB) - What could be the best strategy to mitigate, workaround or fix the problem? Switch the storage Engine to something like this? https://github.com/capacitor-community/sqlite

First: I think adding comments to the reported bug on webkit.org.

Also I changed my logic in code: I try to .get or .set in a loop and added a try catch block, if the catch block is triggered, I try it 10 times again, after that I try to reconnect the database (this.storage.create()), and try to access .get or .set again 10 times, if this is not working, I throw an error with a popup which can't be closed by the user, informing them whats happening and asking them to close or reload the application (button applied). All calls with a timeout of 100ms to not float.

Secondly, I've attached to the resume event.

this.platform.resume.subscribe

Then I access a database key, and if this one is failing I also throw an error popup. This will "solve" that users add data which can't be saved.

Also I've encountered that this issue is mainly when the application is minimized and opened up later again. Normally this issue didn't occure when first-starting the application.

[banjerluke]

My users are also being affected by this issue, though not via ionic-storage but Dexie (still IndexedDB though). FYI, I posted a new bug on bugs.webkit.org: https://bugs.webkit.org/show_bug.cgi?id=273827