Hi, I ask for explanation regrading field TOTAL_SIZE in v$pdbs.

Using Oracle 12c, and having PDB name PDB1

Query:

SQL> select total_size / 1024 /1024 from v$pdbs;

TOTAL_SIZE/1024/1024

--------------------

            7883.375

But:

SQL> select sum(bytes) / 1024 /1024 from dba_data_files;

SUM(BYTES)/1024/1024

--------------------

           31595.375

(and this is even without taking into account  tempfile and logfile!)

On the OS level (only datafiles resides here)

% du -sm pdb1

32458   pdb1

so, what is TOTAL_SIZE actually contains? it doesn't show used space because querying frees pace shows more the 90% usages.

I retried with other pdbs, same results, always TOTAL_SIZE value is much smaller then the actual size.

I'll appreciate if someone can clarify it for me.