Re: [HACKERS] Floating point error

On Tue, Mar 5, 2013 at 10:23 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Why the discrepancy between
>> default behavior and what pg_dump gets?
>
> Basically, the default behavior is tuned to the expectations of people
> who think that what they put in is what they should get back, ie we
> don't want the system doing this by default:
>
> regression=# set extra_float_digits = 3;
> SET
> regression=# select 0.1::float4;
>    float4
> -------------
>  0.100000001
> (1 row)
>
> regression=# select 0.1::float8;
>        float8
> ---------------------
>  0.10000000000000001
> (1 row)
>
> We would get a whole lot more bug reports, not fewer, if that were
> the default behavior.

Isn't this a client rendering issue, rather than an on-the-wire encoding issue?