On Wed, Mar 21, 2012 at 10:35 PM, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:
>> Numeric values are physically stored without any extra leading or
>> trailing zeroes. Thus, the declared precision and scale of a column
>> are maximums, not fixed allocations. (In this sense the numeric type
>> is more akin to varchar(n) than to char(n).) The actual storage
>> requirement is two bytes for each group of four decimal digits,
>> plus five to eight bytes overhead.
>
> The last sentence of the above seems not to be correct. Because,
> thanks to the reduction of NUMERIC size (committed in 9.1), its header
> size is three, five or eight for now. Attached patch fixes this.

Nice catch.  Committed.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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• NUMERIC size at 2012-03-22 02:35:40 from Fujii Masao

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