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V8 automatically optimizes objects with the same shape into efficient structs, making array of objects much more efficient than in Java. And the manually manag
by kykat 7mo ago
V8 automatically optimizes objects with the same shape into efficient structs, making array of objects much more efficient than in Java.
And the manually manager int array acts more like system memory, it's not continuous, so you could have point i 0 and 2 and the data would be:
[1, 2, 3, x, x,x, 3, 2, 1] (3D points).
So I am not describing a struct of arrays.
- spankalee 7mo agoHidden class optimizations just make JavaScript objects behave a little more like Java class instances, where the VM knows where to find each field, rather than having to look it up like a map. It doesn't make JS faster than Java, it makes it almost as fast in some cases.
- kykat 7mo agoI can only say what I observed in testing, and that's that having millions of instances of a class like Point3D{x, y, z} in JS uses significantly less memory than in Java (this was tested on Android, not sure if relevant). It was quite some time ago so I don't remember the details.
- gf000 7mo agoWell, Android is not running Java, it runs Android runtime (dalvik) byte code. In general, depending on when it was, that runtime is much much simpler and does a lot more at compile time at the expense of less JIT optimization. It's also many versions behind the Java API (depending on when it happened). So your data point is basically completely irrelevant.
- lern_too_spel 7mo ago"Efficient structs" in v8 are just inefficient Java classes. https://www.dashlane.com/blog/how-is-data-stored-in-v8-js-engine-memory https://www.dashlane.com/blog/how-is-data-stored-in-v8-js-en... The optimization you discussed for GIS data is called struct of arrays. JavaScript does not do that automatically for you. You would have to do the same thing manually in JavaScript to avoid per-triple object overhead.