Re: Change BgWriterCommLock to spinlock

Qingqing Zhou <zhouqq@cs.toronto.edu> writes:
> On Sun, 8 Jan 2006, Tom Lane wrote:
>> Why is this a good idea?

> "In spirit of incremental improvement":
> (1) The spinlock itself are light weight than the LWLock here and we can
> reduce the lock contention a little bit in AbsorbFsyncRequests();

Spinlock-based coding is inherently much more fragile than LWLock-based
coding.  I'm against changing things in that direction unless a
substantial performance improvement can be gained.  You didn't offer
any evidence of improvement at all.

> (2) Don't need the CRITICAL SECTION in AbsorbFsyncRequests() any more;

Really?  I think this coding still breaks, rather badly, if
RememberFsyncRequest fails.  Certainly the reasons for needing a
critical section have nothing to do with what kind of lock is used.

            regards, tom lane