How to drop users tablespace

Question

Hey to all
     I want to drop USER tablespace wid data file but as we know many oracle users Scott OE data reside in users. How can I protect their data. One method which I read on net to export and import once again is quite cumbersome I run this query
SELECT
owner
, segment_name
, segment_type
FROM
dba_segments
WHERE
tablespace_name='USERS'
it give me two user OE and SCOTT. How can I protect their data before drop the user tablespace

Answer 1

Hi..
As you said direct load takes place, then the rows which are inserted are always inserted above the HWM.So the datafile size size kept on increasing.
i read about segment advisor i run the advisor it shrink the segment but users tablespace size on OS still 200 GB could anyone tell why??You would have run alter table <table_name> shrink space; -- This statement will procede in two steps:
- The first step makes the segment compact by moving rows further down to free blocks at the beginning of the segment.
- The second step adjusts the high watermark. For this Oracle needs an exclusive table lock,but for a very short moment only.
The HWM goes below, and table are now more well organized.This command doesn't resize the datafile at the OS level.So, the datafile sizes will remain the same.One thing which you can do is resize(decrease) the datafile.
MINIMUM DATAFILE SIZE
COLUMN block_size NEW_VALUE v_block_size
SELECT TO_NUMBER(value) AS block_size
FROM   v$parameter
WHERE  name = 'db_block_size';
COLUMN tablespace_name FORMAT A20
COLUMN file_name FORMAT A50
COLUMN current_bytes FORMAT 999999999999999
COLUMN shrink_by_bytes FORMAT 999999999999999
COLUMN resize_to_bytes FORMAT 999999999999999
SET VERIFY OFF
SET LINESIZE 200
SELECT a.tablespace_name,
       a.file_name,
       a.bytes/1024/1024 AS current_MB,
       (a.bytes - b.resize_to)/1024/1024 AS shrink_by_MB,
       b.resize_to/1024/1024 AS resize_to_MB
FROM   dba_data_files a,
       (SELECT file_id, MAX((block_id+blocks-1)*&v_block_size) AS resize_to
        FROM   dba_extents
        GROUP by file_id) b
WHERE  a.file_id = b.file_id
ORDER BY a.tablespace_name, a.file_name;Edited by: Anand... on Feb 17, 2009 12:01 PM