The benchmark is run 5 times without flushing file system caches. If you mmap it... | Hacker News

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		rockwotj on Jan 4, 2024 \| parent \| context \| favorite \| on: The One Billion Row Challenge The benchmark is run 5 times without flushing file system caches. If you mmap it, it will still be in memory between process runs. The author intended this FWIW

mgaunard on Jan 4, 2024 | [–]

That sounds like a benchmarking flaw.

But then, writing good benchmarks is an art in itself.

PaulDavisThe1st on Jan 4, 2024 | [–]

If the cache is not flushed, it will still be in memory between runs whether you mmap it or not.

marginalia_nu on Jan 4, 2024 | [–]

That depends a lot on the OS. I would not count on a 13 GB file being cached in RAM after having been read through once.

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