Refresh database through exp/imp

Question

version 10203 on windows (old db on solaris 8170)
i Have to refresh database data, No of users/schemas are 400+. fastest way to do that would be to do full exp/imp.
but 1st drop current users cascade. (any command to drop all users in with one command?)
then validate all all tables/schemas are same & up-to-date( any suggestion to validate this efficiently?) i am thinking to check full exp logs on old & new db.(what that can take forever manually going through thousands of tables etc)

Answer 1

First, make sure that statistics are properly gathered in both the old and the new DB.
Next, use num_rows column in dba_tables. Since statistics are typically gathered by sampling, they would not necessarily match. They need to be quite close though.
After you are sure that all objects were transferred, you can issue a query to find all tables with “invalid” number of records.
The query can look something like this:
select s.owner, d.table_name , d.num_rows
from dba_tables d
where d.owner not in (‘SYS’,’SYSTEM’,…)
and not exists
           (select * from dba_tables@old_db s
          Where d.owner = s.owner
          And d.table_name = s.table_name
          And s.num_rows between 0.9*d.num_rows and 1.1*d.num_rows
          )You need to take care of some special cases, such as num_rows being NULL, partitioned tables, etc.
Iordan Iotzov
http://iiotzov.wordpress.com/