Horton

Re: Ryu floating point output patch

Andrew Gierth <andrew@tao11.riddles.org.uk>

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From: Andrew Gierth <andrew@tao11.riddles.org.uk>
To: "pgsql-hackers\@postgresql.org" <pgsql-hackers@postgresql.org>
Cc: "David G. Johnston" <david.g.johnston@gmail.com>, Donald Dong <xdong@csumb.edu>, Andres Freund <andres@anarazel.de>, Robert Haas <robertmhaas@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Chapman Flack <chap@anastigmatix.net>
Date: 2019-02-01T19:01:49Z
Lists: pgsql-hackers

Attachments

Latest patch.

No semantic changes; fixes postgresql.conf.sample and adds docs.

In the absence of feedback to the contrary, I've documented the current
behavior of extra_float_digits. I've also removed language from the docs
regarding non-IEEE float formats, and made it clear that all supported
platforms now use IEEE format (whether or not they implement the actual
arithmetic correctly).

I thought of what might be a good reason to leave float->numeric
conversions alone: since they're currently immutable (unlike float
output), they might appear in indexes, and pg_upgrade would have to cope
with that. I'm therefore going to consider float to numeric conversion
as being an issue for a separate patch if at all, rather than part of
this one.

-- 
Andrew (irc:RhodiumToad)

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.