The one that comes to mind is how big your hash maps have to get before all the clever algorithms beat linear scan, and it's surprisingly large on modern computers: linear memory access is _very_ predictable.

The Roc and Zig folks probably have actual numbers.

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tshaddox 3 hours ago | parent [-]

What are these surprisingly large numbers you've seen? I thought that linear scan optimizations are typically reserved for pretty small maps, like dozens or maybe hundreds of elements.

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inigyou an hour ago | parent [-]

Hundreds sounds about right, maybe up to a thousand.

But nobody expects that. Hashmap is supposed to be faster once you have, like, ten elements. That's what was promised to us.

	▲	zellyn an hour ago \| parent [-]
		Yeah, I found hundreds surprising (although not on reflection).