Re: PG 12 draft release notes

Hi,

On 2019-05-21 00:08:25 +0100, Andrew Gierth wrote:
> >>>>> "Andres" == Andres Freund  writes:
> 
>  Andres> Any chance for you to propose a text?
> 
> This is what I posted before; I'm not 100% happy with it but it's still
> better than any of the other versions:

>  * Output REAL and DOUBLE PRECISION values in shortest-exact format by
>    default, and change the behavior of extra_float_digits
> 
>    Previously, float values were output rounded to 6 or 15 decimals by
>    default, with the number of decimals adjusted by extra_float_digits.
>    The previous rounding behavior is no longer the default, and is now
>    done only if extra_float_digits is set to zero or less; if the value
>    is greater than zero (which it is by default), a shortest-precise
>    representation is output (for a substantial performance improvement).
>    This representation preserves the exact binary value when correctly
>    read back in, even though the trailing digits will usually differ
>    from the output generated by previous versions when
>    extra_float_digits=3.

Definitely better from what's there in my opinion. Shortening it if
reasonable wouldn't hurt. Perhaps

Output REAL and DOUBLE PRECISION values in shortest-exact format by
default, and change the behavior of extra_float_digits (...)

When extra_float_digits is set to a value greater than zero (the
default), a shortest-precise representation is output (for a substantial
performance improvement). This representation preserves the exact binary
value when correctly read back in, even though the trailing digits will
usually differ from the output generated by previous versions when
extra_float_digits=3.

Previously, float values were output rounded to 6 or 15 decimals by
default, with the number of decimals adjusted by
extra_float_digits. This behaviour can be restored by setting
extra_float_digits is set to zero or less.

Or something in that vein?

Greetings,

Andres Freund