Re: Reducing the overhead of NUMERIC data - Mailing list pgsql-hackers

Simon Riggs wrote:

> On PostgreSQL, CHAR(12) is a bpchar datatype with all instantiations of
> that datatype having a 4 byte varlena header. In this example, all of
> those instantiations having the varlena header set to 12, so essentially
> wasting the 4 byte header.

We need the length word because the actual size in bytes is variable,
due to multibyte encoding considerations.

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support