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Check reclaimable space

ProDBA
Member Posts: 120 Blue Ribbon
We would like to know how much space can be reclaimed from a table. Here is the example. The following query show the space occupied by the table:
SELECT * FROM (SELECT segment_name, bytes/1024/1024 size_mb FROM dba_segments where owner = 'ADMIN1' and segment_name='T4'); SEGMENT_NAME SIZE_MB ------------------------------ ---------- T4 12
Table T4 has the following number of rows:
SQL> select count(*) from admin1.T4; COUNT(*) ---------- 72374
After deleting all rows, the table it still shows the same size.
SQL> delete admin1.t4; 72374 rows deleted. SQL> commit; Commit complete. SQL> select count(*) from admin1.t4; COUNT(*) ---------- 0 SQL> SELECT * FROM (SELECT segment_name, bytes/1024/1024 size_mb FROM dba_segments where owner = 'ADMIN1' and segment_name='T4'); 2 SEGMENT_NAME SIZE_MB ------------------------------ ---------- T4 12 SQL>
I know how to reclaim this space. But we need to prepare a report where we need to mention that, for example, X MBs can be re-claimed from table T4.
Answers
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Answered here: Reorganize storage structure — oracle-tech