Re: Re: [GENERAL] Trouble with float4 afterupgrading from 6.5.3 to 7.0.2 - Mailing list pgsql-hackers

From Philip Warner
Subject Re: Re: [GENERAL] Trouble with float4 afterupgrading from 6.5.3 to 7.0.2
Date
Msg-id 3.0.5.32.20000809014016.0308eb10@mail.rhyme.com.au
Whole thread Raw
In response to Re: Re: [GENERAL] Trouble with float4 afterupgrading from 6.5.3 to 7.0.2  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Re: [GENERAL] Trouble with float4 afterupgrading from 6.5.3 to 7.0.2
List pgsql-hackers
At 10:04 8/08/00 -0400, Tom Lane wrote:
>
>No.  What float4-to-text really does is *discard* information, by
>rounding off the printed result to only 7 digits (when there are
>actually 7-and-change in there).  This means values that are actually
>distinct float4 values may get printed as the same thing:
>

Thanks guys for some remarkably patient explanations. I now know more than
I want to know about float values.


>I don't much care for this behavior (since it means dump and reload of
>float columns is lossy), and I certainly won't hold still for
>introducing it into other operations on floats.

This makes me think that some kind of binary dump in pg_dump is probably
not a bad idea. Has anybody looked at doing a cross-platform binary COPY?
Or some other way of representing base types - we have <type>in/out maybe
<type>exp/imp (export/import) might be useful to get a portable, lossless
representation.


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