Horton

Re: Ryu floating point output patch

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: Robert Haas <robertmhaas@gmail.com>, Andrew Gierth <andrew@tao11.riddles.org.uk>, Chapman Flack <chap@anastigmatix.net>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2019-01-11T19:54:55Z
Lists: pgsql-hackers 
Andres Freund <andres@anarazel.de> writes:
> And of course it'd change the dump's text contents between ryu and
> non-ryu backends even with extra_float_digits = 3, but the resulting
> floats ought to be the same. It's just that ryu is better at figuring
> out what the minimal text representation is than the current code.

I'm fairly concerned about this blithe assertion that the ryu code is
smarter than the rest of the world.  In particular, how does it know
how every strtod() on the planet will react to specific input?

			regards, tom lane

Commits

  1. Provide an extra-float-digits setting for pg_dump / pg_dumpall

  2. Change floating-point output format for improved performance.

  3. Use strtof() and not strtod() for float4 input.