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

From: The Hermit Hacker <scrappy(at)hub(dot)org>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Alfred Perlstein <bright(at)wintelcom(dot)net>, Xu Yifeng <jamexu(at)telekbird(dot)com(dot)cn>, "Mikheev, Vadim" <vmikheev(at)SECTORBASE(dot)COM>, Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>, Peter Eisentraut <peter_e(at)gmx(dot)net>, <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Re[4]: Allowing WAL fsync to be done via O_SYNC
Date: 2001-03-16 17:10:34
Message-ID: Pine.BSF.4.33.0103161309330.72183-100000@mobile.hub.org
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On Fri, 16 Mar 2001, Tom Lane wrote:

> Alfred Perlstein <bright(at)wintelcom(dot)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 ...

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