Database Size calculation

Question

Hi,
i have given a DB not sure of the size but its more than 50 or 100gb so how can i check the size of the entire database using the query.
i tried these
SELECT SUM(BYTES)/1024/1024 "MB" FROM DBA_SEGMENTS ;
giving me 1 GB
and
select sum(bytes / (1024*1024)) "DB Size in MB" from dba_data_files; gave me 1.6gb so something is wrong.
can someone provide me the exact query to get the complete size of an database.
Thanks

Answer 1

Your queries are correct..
SELECT SUM(BYTES)/(1024*1024*1024) from dba_data_files; --Size in GB
plus
SELECT SUM(BYTES)/(1024*1024*1024) from dba_temp_files;
plus
SELECT SUM(BYTES)/(1024*1024) from V$LOG --Size in MB
They should tell you the size of the database.
DBA_SEGMENTS will give you the size that has been allocated to the segments. This will be less than the size in dba_data_files total size
Edited by: user12035575 on Sep 7, 2011 8:04 PM