From: | Bruce Momjian <bruce(at)momjian(dot)us> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: posix_fadvise versus old kernels |
Date: | 2006-06-27 18:41:56 |
Message-ID: | 200606271841.k5RIfuk27717@momjian.us |
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Lists: | pgsql-hackers |
Tom Lane wrote:
> I've been digging into why buildfarm member thrush has been dumping core
> consistently during the regression tests since the posix_fadvise patch
> went in. I've confirmed that posix_fadvise() itself will SIGSEGV in a
> standalone test program, and found that this happens only if
> _FILE_OFFSET_BITS=64 ... which is our default configuration on Linux.
>
> Some googling turned up the following
> http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=313219
> which basically says that posix_fadvise64 + 2.4 kernel + older glibc
> = crash. It sounds like the 2.4 kernel hasn't got this call but glibc
> thought it did, up till about a year ago.
>
> While we could possibly come up with a suitable configure test to
> determine whether posix_fadvise is actually safe to use on a given
> system, I think we should seriously consider just reverting the patch.
> As far as I saw, zero evidence was given that it actually does anything
> measurable. Without a benchmark to prove that it's worth spending more
> time on, I'm disinclined to trouble over it.
Agreed. How about if we just #ifdef NOT_USED the code and mention the
problem in a comment.
--
Bruce Momjian bruce(at)momjian(dot)us
EnterpriseDB http://www.enterprisedb.com
+ If your life is a hard drive, Christ can be your backup. +
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