IndexedDB write performance

[MathisBullinger]

No description provided.

[MathisBullinger]

This seems to be an issue of limited IndexedDB write speed or more specifically, how fast IDB resolves its promises. See idb-test repo.

Screen.Recording.2021-10-06.at.03.17.26.mov

[MathisBullinger]

Confirmed that waiting for the displayed IndexedDB storage size to come to rest (takes several minutes for ~8.5 MB) does result in all episodes being persisted in the database.

[MathisBullinger]

next steps:

• don't write episodes in serial
• don't use IDB promises (but IndexedDB directly) for writing episodes
• throttle batch episode writes
• investigate if any other IDB writes block execution

[MathisBullinger]

Using parallel single item transactions in IndexedDB directly for a test set of 1000 records results in virtually the same delays to the .onsucess callback as the IDB promise resolve times.

The timings are consistent with IndexedDB locking the database to perform a single readwrite transaction at a time.

[MathisBullinger]

The same test takes 305 ms in Firefox and 584 ms in Safari.

[MathisBullinger]

This might be due to Chrome's strict durability guarantees. There is a relaxed durability API available in Chrome.

[MathisBullinger]

Performing the same test in Chrome with the transaction option { durability: 'relaxed' } reduces the time to ~700 ms.

[MathisBullinger]

relevant blog post: Speeding up IndexedDB reads and writes

[MathisBullinger]

f1348e0 resolves the issue. Tuning of batch window is TBD