Show HN: OpenHFT Collections – the fastest Java hash sets and maps ever

github.com

4 pointsleventov2 comments

Looks interesting, but it's difficult to understand why it is faster (i.e. the design decisions you made).

From poking around, I can see that you have specialized each collection for the primitive types, to avoid boxing/unboxing. I'm not sure if there's more to it than this though!

I wasn't able to quickly locate the actual storage code though - do you store values as a primitive array or do you use a ByteBuffer? It would also be useful to understand how this compares to e.g. Trove.

Just some friendly feedback - project looks awesome; thanks for open-sourcing it.

Comarison with Trove and other primitive collections libs: http://java.dzone.com/articles/time-memory-tradeoff-example

Why faster:

- no supplemental "states" array in open adressing implementation

- keys and values are stored "in parallel" in the single array, whenever possible: https://github.com/OpenHFT/hftc/issues/23

- generally, attention to the finest detail in implementation

There is no "actual storage code" - it is 95% generated.

Thank you.

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