Thanks for the analysis. I have removed mention of the -fast option
from the Solaris FAQ.
---------------------------------------------------------------------------
Kenneth Marshall wrote:
> On Wed, Sep 27, 2006 at 04:09:18PM +0200, Zdenek Kotala wrote:
> > Tom Lane napsal(a):
> > >Zdenek Kotala <Zdenek.Kotala@Sun.COM> writes:
> > >>The problem was generated, because -fast option was set only for the
> > >>compiler and not for the linker. Linker takes wrong version of
> > >>libraries. If -fast is set for both then horology test is OK, but
> > >>question was if float optimalization should generate some problems.
> > >
> > >So FAQ_Solaris needs to tell people to put -fast in both CFLAGS and
> > >LDFLAGS?
> >
> > Exactly, but I want to sure, that float optimalization is safe and
> > should be applied for postgres, because -fast breaks IEE754 standard. If
> > it is OK I will adjust FAQ_Solaris.
> >
> > Zdenek
> >
> Unless the packager understands the floating point usage of every
> piece and module included and the effect that the -fast option will
> have on them, please do not recommend it for anything but extremely
> well tested dedicated use-cases. When it causes problems, it can
> be terrible if the problems are not detected immediately. Massive
> data corruption could occur.
>
> Given these caveats, in a well tested use-case the -fast option can
> squeeze a bit more from the CPU and could be used. I have had to
> debug the fallout from the -fast option in other software in the
> past. Let's just say, backups are a good thing.
>
> I would vote not to recommend it without very strong cautions similar
> to was Sun includes in the compiler manual pages.
>
> Ken
>
>
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