Обсуждение: lower integer bound not supported

According to documentation (from 9.1 to 9.5) the supported
integer ranges are these ones:

 smallint  2 bytes   -32768 to +32767
  integer  4 bytes   -2147483648 to +2147483647
   bigint  8 bytes   -9223372036854775808 to +9223372036854775807

But the lowest bound is not really supported:

  # select -32768::int2;
  ERROR:  smallint out of range
  # select -2147483648::int4;
  ERROR:  integer out of range
  # select -9223372036854775808::int8;
  ERROR:  bigint out of range

This happens with server versions 9.1.22, 9.3.6 and 9.5(unspecified).

Is it the code or the documentation being broken ?
To me, the documentation makes the most sense, and the code is broken.

--strk;

  ()   Free GIS & Flash consultant/developer
  /\   https://strk.kbt.io/services.html

Sandro Santilli wrote:
> According to documentation (from 9.1 to 9.5) the supported
> integer ranges are these ones:
>
>  smallint  2 bytes   -32768 to +32767
>   integer  4 bytes   -2147483648 to +2147483647
>    bigint  8 bytes   -9223372036854775808 to +9223372036854775807
>
> But the lowest bound is not really supported:
>
>   # select -32768::int2;
>   ERROR:  smallint out of range
>   # select -2147483648::int4;
>   ERROR:  integer out of range
>   # select -9223372036854775808::int8;
>   ERROR:  bigint out of range

This is reported every once in a while.  It's not a bug, just an
operator precedence issue: the :: binds more tightly than the unary - so
the number is interpreted as a positive value first, which is indeed out
of range.  Try "(-32768)::int2".

Maybe it would be clearer if the error message indicated what's the
value that's out of range, so that the lack of the minus might make the
problem more evident; and perhaps add a HINT suggesting to add the
parens?

--
Álvaro Herrera                http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

On Wed, Jun 08, 2016 at 12:37:59PM -0400, Alvaro Herrera wrote:
> Sandro Santilli wrote:
> > According to documentation (from 9.1 to 9.5) the supported
> > integer ranges are these ones:
> >
> >  smallint  2 bytes   -32768 to +32767
> >   integer  4 bytes   -2147483648 to +2147483647
> >    bigint  8 bytes   -9223372036854775808 to +9223372036854775807
> >
> > But the lowest bound is not really supported:
> >
> >   # select -32768::int2;
> >   ERROR:  smallint out of range
> >   # select -2147483648::int4;
> >   ERROR:  integer out of range
> >   # select -9223372036854775808::int8;
> >   ERROR:  bigint out of range
>
> This is reported every once in a while.  It's not a bug, just an
> operator precedence issue: the :: binds more tightly than the unary - so
> the number is interpreted as a positive value first, which is indeed out
> of range.  Try "(-32768)::int2".

That explains!

> Maybe it would be clearer if the error message indicated what's the
> value that's out of range, so that the lack of the minus might make the
> problem more evident; and perhaps add a HINT suggesting to add the
> parens?

An HINT suggesting parens would be very very helpful.

--strk;