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

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

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Alfred Perlstein <bright@wintelcom.net>
Cc: 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: 2001-03-16T16:23:39Z
Lists: pgsql-hackers
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.

			regards, tom lane