Re: Issue with the PRNG used by Postgres

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> Oh, yeah ... right. But then why does the comment say that it's
> increasing the delay between a random fraction between 1X and 2X?

I think the comment is meant to say that the new delay value will be
1X to 2X the old value. If you want to suggest different phrasing,
feel free.

> It would certainly be interesting to know which spinlocks were at
> issue, here. But it also seems to me that it's reasonable to be
> unhappy about the possibility of this increasing cur_delay by exactly
> 0.

As I said to Parag, I see exactly no reason to believe that that's a
problem, unless it happens *a lot*, like hundreds of times in a row.
If it does, that's an RNG problem not s_lock's fault. Now, I'm not
going to say that xoroshiro can't potentially do that, because I've
not studied it. But if it is likely to do that, I'd think we'd
have noticed the nonrandomness in other ways.

regards, tom lane