Re: Issue with the PRNG used by Postgres

Hi,

On 2024-04-10 07:55:16 -0700, Parag Paul wrote:
> This is a little bit more complex than that. The spinlocks are taken in the
> LWLock(Mutex) code, when the lock is not available right away.
> The spinlock is taken to attach the current backend to the wait list of the
> LWLock. This means, that this cannot be controlled.
> The repro when it happens, it affects any mutex or LWLock code path, since
> the low hamming index can cause problems by removing fairness from the
> system.

Please provide a profile of a problematic workload.  I'm fairly suspicious
of the claim that RNG unfairness is a real part of the problem here.

Greetings,

Andres Freund