IndexedDB storage backend update: Validation requested

[Akhila Veerapuraju (dhveerap)]

Overview

Chromium is transitioning the IndexedDB backing store from LevelDB to SQLite (Why?), and WebView2 inherits this change. The IndexedDB web API itself is not changing, so we expect this transition to be transparent for most applications.

Before this change is enabled broadly, we’re asking WebView2 developers to validate their applications with the new storage backend and report any unexpected behavior.

The transition is being staged through the IdbSqliteOnDiskRollout feature. Chrome and Edge are experimenting with this change through field trials. Because WebView2 does not participate in Edge experimentation, validation from WebView2 applications provides an important additional safety check.

What happens with UseSqliteForNewStores enabled?

• Newly created IndexedDB stores use SQLite.
• Existing healthy LevelDB stores remain on LevelDB and are not migrated during this stage.
• On disk, SQLite stores use a SQLite database file together with -wal sidecar file, rather than a LevelDB directory.

How to test

Launch your WebView2 application with the following browser argument:

--enable-features=IdbSqliteOnDiskRollout:stage/UseSqliteForNewStores

Then run your normal test suite against the application.

We particularly recommend validating:

• Mixed LevelDB and SQLite states
• Large records and Blob/File data
• Realistic data volumes and performance
• Concurrent IndexedDB access across frames, workers, or WebViews
• Quota limits and error-handling paths
• Data durability across application restarts and abrupt termination
• onupgradeneeded migrations

If your application directly accesses the WebView2 user data folder for scenarios such as backup, antivirus exclusions, disk-usage reporting, or clean-up, please also validate your integration against the new SQLite on-disk layout, including the sidecar files.

Rollback

• If any issues are found during this stage, we will roll back to UseLevelDbForNewStores stage. New stores return to LevelDB, while existing stores of either backend keep opening normally and are not replaced or migrated.
• Please also validate this path (available only from runtime 157.0.4335.0). After testing with UseSqliteForNewStores , restart your application with:
  • --enable-features=IdbSqliteOnDiskRollout:stage/UseLevelDbForNewStores
• Confirm that databases created under SQLite still open with their data intact, that your pre-existing LevelDB databases are unaffected, and that any newly created store uses LevelDB.

Feedback

Please let us know if you encounter any regressions, data integrity issues, performance changes, or other unexpected behavior while testing.