Re: maximum digits for NUMERIC

On Sun, Mar 20, 2011 at 08:14:21PM -0400, Noah Misch wrote:
> On Fri, Mar 11, 2011 at 11:36:14AM +0000, Gianni Ciolli wrote:
> > maybe we should change the "1000 digits" here:
> >
> > http://developer.postgresql.org/pgdocs/postgres/datatype-numeric.html#DATATYPE-NUMERIC-DECIMAL
> >
> > because ISTM that up to 2^17 digits are supported (which makes more
> > sense than 1000).
>
> Agreed. The documentation is suggestive of this limit:
>
> # CREATE TABLE n (c numeric(1001,0));
> ERROR: NUMERIC precision 1001 must be between 1 and 1000
> LINE 1: CREATE TABLE n (c numeric(1001,0));
>
> However, that's indeed just a limit of the numeric typmod representation, not
> the data type itself. An unqualified "numeric" column hits no such limit.

For the record, the limits I found from my tests are:
* 2^17 - 1 maximum total digits
* 2^14 - 1 maximum fractional digits

(I did tests as I couldn't extract any obvious limit from the source
code of numeric.c)

Best regards,
Dr. Gianni Ciolli - 2ndQuadrant Italia
PostgreSQL Training, Services and Support
gianni(dot)ciolli(at)2ndquadrant(dot)it | www.2ndquadrant.it