From: Warren Young
Date: April 2 2008 12:03am
Subject: Re: Loss of float precision
List-Archive: http://lists.mysql.com/plusplus/7552
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Dave Bailey wrote:
> If you view the raw file and look for the definition of
> 
> Item_func_ieee754_to_string::val_str(String *str)
> 
> the comment specifies that 17 digits of precision are needed for double.
> It is also true that 9 digits are needed for single precision.  I didn't
> believe
> it, but I tested it once with every possible value of a single precision
> float
> and found that there were cases where 8 digits was not enough to support
> a lossless conversion from float to string and back.

Well, OK... :)  The patch is in svn now.