Re: pg12 release notes - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: pg12 release notes
Date
Msg-id 20190511142925.vhgur7km7k22e2en@momjian.us
Whole thread Raw
In response to Re: pg12 release notes  (Andrew Gierth <andrew@tao11.riddles.org.uk>)
List pgsql-hackers
On Sat, May 11, 2019 at 03:06:40AM +0100, Andrew Gierth wrote:
> >>>>> "Bruce" == Bruce Momjian <bruce@momjian.us> writes:
>  Bruce> Do I need more?
> 
> That isn't quite how I'd have worded it, but I'm not sure what the best
> wording is. Something like:
> 
>  * 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.
> 
> But I'm not 100% happy with this wording and am entirely open to
> suggestions for improvement.

I went with this paragraph:

    This dramatically speeds up processing of floating-point values but
    causes additional trailing digits to potentially be displayed.  Users
    wishing to have output that is rounded to match the previous behavior
    can set <literal>extra_float_digits=0</literal>, which is no longer the
    default.

Improvements?

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

+ As you are, so once was I.  As I am, so you will be. +
+                      Ancient Roman grave inscription +



pgsql-hackers by date:

Previous
From: Michael Paquier
Date:
Subject: Re: Bug in reindexdb's error reporting
Next
From: Bruce Momjian
Date:
Subject: Re: pg12 release notes