Unable to reclaim the table space

Question

Hi guys,
Today I have tried to reclaim the unused space in table by the below command. The command executed successfully but the space is not reclaimed, I'm not sure why, can you help me out on this.
SQL> select OWNER,SEGMENT_NAME,TABLESPACE_NAME,bytes/1024/1024/1024 as "SIZE IN GB",PCT_INCREASE,EXTENTS,SEGMENT_TYPE,SEGMENT_SUBTYPE  from dba_segments where SEGMENT_NAME in (------------------------------);
OWNER                          SEGMENT_NAME                   TABLESPACE_NAME                SIZE IN GB PCT_INCREASE    EXTENTS SEGMENT_TYPE       SEGMENT_SU
aaa_aaaaa                      yyyy1                     xxx                       7.13555908                     304 TABLE              ASSM
aaa_aaaaa                      yyyy2                             xxx                           9.01885986                     339 TABLE              ASSM
SQL> alter table aaa_aaaaa.yyyy1 shrink space cascade;
Table altered.
SQL>  select OWNER,SEGMENT_NAME,TABLESPACE_NAME,bytes/1024/1024/1024 as "SIZE IN GB",PCT_INCREASE,EXTENTS,SEGMENT_TYPE,SEGMENT_SUBTYPE  from dba_segments where SEGMENT_NAME in (---------------------------);
OWNER                          SEGMENT_NAME                   TABLESPACE_NAME                SIZE IN GB PCT_INCREASE    EXTENTS SEGMENT_TYPE       SEGMENT_SU
aaa_aaaaa                      yyyy1                          xxx                           7.11260986                     304 TABLE              ASSM
aaa_aaaaa                      yyyy2                        xxx                           9.01885986                     339 TABLE              ASSM
The database is 11g, Aix os, this database is used in replication and holds master tables.
Thanks and Regards
Venkata Sudheer.Y

Answer 1

venkata_sudheer wrote:
Hi,
There are only 8000 rows in the table, but its occupying 7GB of space, its not releasing, not sure why its not releasing. I was asked to check that out, but not sure where to start. Is segment advisor free or do we need to pay the license.
Thanks and Regards
VenkataNumber of rows does not exactly mean that your segment size should be small. The row size can actually be that big.
Here is a script that you can use to get a grip of the HWM of the segment:
First gather stats on it:
exec dbms_stats.gather_table_stats(ownname=>'SCHEMA',tabname=>'TABLE_NAME',method_opt=>'for all columns size auto',estimate_percent=>dbms_stats.auto_sample_size,cascade=>true); and then query:
select owner, table_name, to_char(last_analyzed,'dd/mm/yyyy hh24:mi:ss') last_stats, trunc((num_rows*avg_row_len)/1024/1024,2) real_alloc_mb, trunc((blocks*(select BLOCK_SIZE from dba_tablespaces tbs where t.tablespace_name=tbs.tablespace_name))/1024/1024,2) hwm_size_mb,
       100 -round((trunc((num_rows*avg_row_len)/1024/1024,2)*100)/trunc((blocks*(select BLOCK_SIZE from dba_tablespaces tbs where t.tablespace_name=tbs.tablespace_name))/1024/1024,2),2) RECL_PERCENT, chain_cnt
from dba_tables t
where t.table_name IN ('TABLE_NAME');Lastly,does the table have any LOB columns ?