How to check the objects size in DBA_RECYCLEBIN

Question

Hi All,
I want to purge dba_recyclebin, before that i want to check the size of all objects residing in dba_recyclebin.
I am using below query to goup by tablespace.
SELECT TS_NAME, SUM(SPACE*1024)/1024/1024/1024 AS "Size in GB" FROM DBA_RECYCLEBIN GROUP BY TS_NAME order by 2 desc
Kindly inform me is the correct way to check it. for example if the 10gb space is shown from this query, will i able to see 10GB free space after purging. Kindly confirm
Thanks
Krishna

Answer 1

I am using below query to goup by tablespace.
SELECT TS_NAME, SUM(SPACE*1024)/1024/1024/1024 AS "Size in GB" FROM DBA_RECYCLEBIN GROUP BY TS_NAME order by 2 desc
As I mentioned, the SPACE field is in terms of BLOCKS rather than bytes.
First confirm your database block size using
SQL> show parameter db_block_size
then modify the query as
SQL> SELECT TS_NAME, SUM(SPACE*<DB_BLOCK_SIZE>)/1024/1024/1024 AS "Size in GB" FROM DBA_RECYCLEBIN GROUP BY TS_NAME order by 2 desc;
I am quite sure the db_block_size in your database is 8192.
Since you have used 1024 instead 8192 as the block size, you are seeing the difference in DBA_RECYCLEBIN and DBA_SEGMENTS