Backup of large objects

Hi,
 we are going to use postgresql and we  have some doubts about it
.
1) How to backup Large objects, because pg_dump will not backup
the large
objects. Can anybody help with some examples.

2)How big is the database that postgresql can support?

3)How to change the size and datatype of   a column in a table.
Because, no where in the documentation it is mentioned.

4) Up to which point can  the data be  restored? Is it upto the
point of
backup taken or upto the point of system crash?

5) How many connection does it support at a time?


Thanks,
chava
--

Srinivasa R Chava (Chava) <s.chava@wcom.com>
Application Developer
Corporate Intra/Internet Systems
WORLDCOM - http://www.worldcom.com/ - NASDAQ:WCOM
500 Clinton Center Drive (Corporate Headquarters)
Clinton, Mississippi (MS) USA  39056
(601)460-3122 / vnet4603122 / (800)844-1009 / FAX(601)460-8257