Compressed table using oracle advanced compression but space is not release

Question

Dear Experts,
I am using oracle 11.2.0.2 with sap as application
I have compressed one of my largest indetified table "SWWCNTP0" as per below statement
Alter table sapsr3.SWWCNTP0 compress for oltp;
After this i have performed reorg for the above table but it doesnt released the space
before reorg 39gb
after reorg 39g
Please advice
Regards
Navin Somal

Answer 1

906078 wrote:
Dear Experts,
I am using oracle 11.2.0.2 with sap as application
I have compressed one of my largest indetified table "SWWCNTP0" as per below statement
Alter table sapsr3.SWWCNTP0 compress for oltp;
After this i have performed reorg for the above table but it doesnt released the space
before reorg 39gb
after reorg 39g
Please advice
Regards
Navin SomalHow did you go about doing the reorg?
He's a simple working example ...
ME_ORCL?create table to_compress as
  2  select * from all_objects
  3  union all
  4  select * from all_objects
  5  union all
  6  select * from all_objects
  7  union all
  8  select * from all_objects
  9  union all
10  select * from all_objects;
Table created.
Elapsed: 00:00:16.74
ME_ORCL?select bytes
  2  from dba_segments
  3  where segment_name = 'TO_COMPRESS';
             BYTES
          44040192
1 row selected.
Elapsed: 00:00:00.06
ME_ORCL?alter table to_compress compress for oltp;
Table altered.
Elapsed: 00:00:00.09
--we don't expect any change here, because this only affects subsequent operations on the table, we need to MOVE the table to see any benefits in the existing data
ME_ORCL?select bytes
  2  from dba_segments
  3  where segment_name = 'TO_COMPRESS';
             BYTES
          44040192
1 row selected.
Elapsed: 00:00:00.08
ME_ORCL?alter table to_compress move compress for oltp;
Table altered.
Elapsed: 00:00:01.08
ME_ORCL?select bytes
  2  from dba_segments
  3  where segment_name = 'TO_COMPRESS';
             BYTES
          14680064
1 row selected.
Elapsed: 00:00:00.02
ME_ORCL?