Re: Proposal of tunable fix for scalability of 8.4

>>> Scott Carey <scott@richrelevance.com> wrote:
> "Kevin Grittner" <Kevin.Grittner@wicourts.gov> wrote:
>
>> I'm a lot more interested in what's happening between 60 and 180
>> than over 1000, personally.  If there was a RAID involved, I'd put
>> it down to better use of the numerous spindles, but when it's all
>> in RAM it makes no sense.
>
> If there is enough lock contention and a common lock case is a short
> lived shared lock, it makes perfect sense sense.  Fewer readers are
> blocked waiting on writers at any given time.  Readers can 'cut' in
> line ahead of writers within a certain scope (only up to the number
> waiting at the time a shared lock is at the head of the queue).
> Essentially this clumps up shared and exclusive locks into larger
> streaks, and allows for higher shared lock throughput.

You misunderstood me.  I wasn't addressing the affects of his change,
but rather the fact that his test shows a linear improvement in TPS up
to 1000 connections for a 64 thread machine which is dealing entirely
with RAM -- no disk access.  Where's the bottleneck that allows this
to happen?  Without understanding that, his results are meaningless.

-Kevin