Intent to Ship: IndexedDB relaxed durability transactions

[Adrienne Walker]

Contact emails

en...@chromium.org

Spec change discussion

https://github.com/w3c/IndexedDB/issues/50

Spec

https://w3c.github.io/IndexedDB/#transaction-durability-hint

https://github.com/w3c/IndexedDB/commit/1a519e7f0a12de4acffc641d3254c1c2d34d380a

Summary

Allow developers to explicitly trade off durability for performance.

Currently after writing an IndexedDB transaction, Firefox does not flush to disk but Chrome does. This flush increases the durability (in the ACID sense) in that the transaction will be guaranteed to have been written all the way to disk rather than merely to an intermediate OS cache. However, this comes with a significant performance cost. On one test benchmark, not flushing caused a 10X+ performance improvement in adding new objects to a database.

Mechanically, this change adds a durability hint to IDBTransactionOptions.  If not specified, this hint has the value "default" which tells the user agent to use the default durability behavior.  A developer may now further specify "strict" (current behavior) or "relaxed" (faster new behavior) for this option.

Link to “Intent to Prototype” blink-dev discussion

https://groups.google.com/a/chromium.org/d/msg/blink-dev/aDDJXM8TZnk/xdhSlY-ZDwAJ

Is this feature supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)?

Yes.

Risks

Interoperability and Compatibility

Code using the new durability option will still run correctly on browsers that don't implement this feature, with degraded performance.

Firefox: No public signals. A position request has been filed (https://github.com/mozilla/standards-positions/issues/254), and the API surface here was co-designed with a Mozillan, but there is no official position.

Edge: No public signals

Safari: Opposed.  Opposed to a previous proposal to make transactions non-durable by default, but no feedback on this proposal.

Web Developers: No signals

Ergonomics

There are no known risks associated with ergonomics.

Activation

This feature will be easy for developers to take advantage of immediately.

Is this feature fully tested by web-platform-tests? Link to test suite results from wpt.fyi.

https://wpt.fyi/results/IndexedDB/transaction-relaxed-durability.tentative.any.html

Entry on the feature dashboard

https://chromestatus.com/feature/5730701489995776

[Boris Zbarsky]

On 2/14/20 6:38 PM, Adrienne Walker wrote:
> Firefox: No public signals. A position request has been filed
> (https://github.com/mozilla/standards-positions/issues/254

> <https://github..com/mozilla/standards-positions/issues/254>), and the

> API surface here was co-designed with a Mozillan, but there is no
> official position.

Adrienne,

Thank you; this is very much appreciated!

-Boris

[Daniel Bratell]

LGTM1

In general it would have been good to have had more vendor buy-in, but it's clear that other vendors don't see this as a prioritized area so I see no need to wait any longer. Especially since the compatibility risk is low (it's only a hint and hopefully it will rarely matter, unless the data is never ever flushed).

/Daniel

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[Chris Harrelson]

LGTM2

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[Yoav Weiss]

LGTM3

As Daniel points out, the interop risk here is low as it's defined as a hint.

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