On Fri, Mar 20, 2009 at 7:39 PM, Jignesh K. Shah <J.K.Shah@sun.com> wrote:
> Alvaro Herrera wrote:
>>> So Simon's correct.
>> And perhaps this explains why Jignesh is measuring an improvement on his
>> benchmark. Perhaps an useful experiment would be to turn this behavior
>> off and compare performance. This lack of measurement is probably the
>> cause that the suggested patch to fix it was never applied.
>>
>> The patch is here
>> http://archives.postgresql.org//pgsql-hackers/2004-11/msg00935.php
>
> One of the reasons why my patch helps is it keeps this check intact but
> allows other exclusive Wake up.. Now what PostgreSQL calls "Wakes" is in
> reality just makes a variable indicating wake up and not really signalling a
> process to wake up. This is a key point to note. So when the process wanting
> the exclusive fights the OS Scheduling policy to finally get time on the CPU
> then it check the value to see if it is allowed to wake up and potentially
I'm confused. Is a process waiting for an LWLock is in a runnable
state? I thought we went to sleep on a semaphore.
...Robert