Re: Re: [Oledb-dev] double precision error with pg linux server, but not with windows pg server

From: Shachar Shemesh <shachar(at)shemesh(dot)biz>
To: Peter Eisentraut <peter_e(at)gmx(dot)net>
Cc: pgsql-hackers(at)postgresql(dot)org, Greg Smith <gsmith(at)gregsmith(dot)com>, oledb-devel(at)pgfoundry(dot)org
Subject: Re: Re: [Oledb-dev] double precision error with pg linux server, but not with windows pg server
Date: 2007-05-21 14:02:49
Message-ID: 4651A689.6010909@shemesh.biz
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Peter Eisentraut wrote:

> "I want to use the binary format but I don't like what it does."
It doesn't do anything. The set of circumstances under which it is
useful has been limited, on purpose, and, as far as I can see, without
any good reason. Spending not much time (and I suggested to spend it
myself, so it's not like I'm asking anyone to do this for me) this
format can be made to allow transfer of data between installations. Why
wouldn't we want that?

> We have fought many years to get closer to IEEE 754
> conformance.

Please notice that the format I offered *is* IEEE. In fact, what I'm
offering is to export the binary in IEEE format EVEN IF THE NATIVE
FORMAT ISN'T.

As for the ARM architecture, I've pulled my sources, and the answer is
this: ARM doesn't have one standard floating point format. Different ARM
architectures will use different formats. Most architectures will
actually use IEEE, but some will use decimal based and such. According
to my source (a distributor of ARM based hardware), none of the other
formats will lose precision if translated to IEEE.

So, I will repeat my original question. I can write portable code that
will translate the native format to IEEE (if it's not already the same).
It seems that it will be good enough for all platforms discussed here.
Failing that, we can adopt my later proposal which is IEEE + status for
all places where that is good enough.

Shachar

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