Re: [HACKERS] A design for amcheck heapam verification

On Thu, Feb 8, 2018 at 6:05 AM, Andrey Borodin <x4mmm@yandex-team.ru> wrote:
> I do not see a reason behind hashing the seed.

It made some sense when I was XOR'ing it to mix. A uniform
distribution of bits seemed desirable then, since random() won't use
the most significant bit -- it generates random numbers in the range
of 0 to 2^31-1. It does seem unnecessary now.

> Also, I'd like to reformulate this paragraph. I understand what you want to say, but the sentence is incorrect.
> + * The Bloom filter behaves non-deterministically when caller passes a random
> + * seed value.  This ensures that the same false positives will not occur from
> + * one run to the next, which is useful to some callers.
> Bloom filter behaves deterministically, but differently. This does not ensures any thing, but probably will give
somethingwith hight probability.
 

I agree that that's unclear. I should probably cut it down, and say
something like "caller can pass a random seed to make it unlikely that
the same false positives will occur from one run to the next".

-- 
Peter Geoghegan