Re: Re[4]: Allowing WAL fsync to be done via O_SYNC

Marc G. Fournier <scrappy@hub.org>

From: The Hermit Hacker <scrappy@hub.org>

To: Tom Lane <tgl@sss.pgh.pa.us>

Cc: Alfred Perlstein <bright@wintelcom.net>, Xu Yifeng <jamexu@telekbird.com.cn>, "Mikheev, Vadim" <vmikheev@SECTORBASE.COM>, Bruce Momjian <pgman@candle.pha.pa.us>, Peter Eisentraut <peter_e@gmx.net>, <pgsql-hackers@postgresql.org>

Date: 2001-03-16T17:10:34Z

Lists: pgsql-hackers

On Fri, 16 Mar 2001, Tom Lane wrote:

> Alfred Perlstein <bright@wintelcom.net> writes:
> >> definitely need before considering this is to replace the existing
> >> spinlock mechanism with something more efficient.
>
> > What sort of problems are you seeing with the spinlock code?
>
> It's great as long as you never block, but it sucks for making things
> wait, because the wait interval will be some multiple of 10 msec rather
> than just the time till the lock comes free.
>
> We've speculated about using Posix semaphores instead, on platforms
> where those are available.  I think Bruce was concerned about the
> possible overhead of pulling in a whole thread-support library just to
> get semaphores, however.

But, with shared libraries, are you really pulling in a "whole
thread-support library"?  My understanding of shared libraries (altho it
may be totally off) was that instead of pulling in a whole library, you
pulled in the bits that you needed, pretty much as you needed them ...