Re: [PATCHES] Win32 CHECK_FOR_INTERRUPTS() performance

On Mon, 24 Oct 2005, Tom Lane wrote:

>
> Are we all comfortable that
> http://archives.postgresql.org/pgsql-hackers/2005-10/msg01009.php
> is OK to apply?
>
> regards, tom lane

I tried to persuade myself that removing all WaitForSingleObjectEx() is
safe ... the thing is we will false alarm EINTR as Magnus said (details to
repeat it are list below in case). There are several EINTR in the code,
semop() calls, socket() calls, ..., seems they are all ok except
pgwin32_backend_usleep() changes a little bit performance: it can't sleep
enough because of the false alarm, but it is ok though.

Conclusion: Agree to apply.

Regards,
Qingqing

---
Consider a sequence like this:

1. I am killing you signal A:

enter_crit;
set signal bit;
leave_crit;

2. You CHECK_FOR_INTERRUPTS():
enter_crit;
sig(A);
ResetEvent();
leave_crit;

3. I finish my killing:
SetEvent();

Now the event is signaled but the signal is handled already.