Re: lwlocks and starvation

On Wed, 2004-11-24 at 23:30 -0500, Tom Lane wrote:
> It is not a 100% solution because it does not
> cover the case where a waiting exclusive locker is released, then a new
> shared locker arrives at the lock before the exclusive locker is given
> any cycles to acquire the lock.  However I don't see any cure for the
> latter problem that's not worse than the disease

Yeah, I don't think this is a problem -- eventually the exclusive waiter
will win the coin flip anyway.

> On the other hand we might consider that this isn't a big problem and
> just leave things as they are.  We haven't seen any indication that
> starvation is a real problem in practice, and so it might be better to
> avoid extra trips through the kernel scheduler.

Yes, I'm a little concerned about applying a patch to address what is,
so far, an entirely academic concern -- especially if it might hurt
performance.

-Neil