Files that make up a tablespace

Question

Hi,
I understand that a tablespace is the lowest level logical entity for storing data and that it can be made up of several physical files.
What I am unclear about is how Oracle distributes the data in the physical files (i.e. say I have TB01 (3GB) made up of 3 files TB01_01.ORA (1GB), TB01_02.ORA (1GB) and TB01_03.ORA (1GB). The tablespace is initially empty. If I create a table for one of the schemas using tablespace TB01 and insert enough rows to occupy 1/3 of the tablespace then how should I expect to see the data distribution in the physical files ? ).
I guess my question could be read as :
Is it necessary or even recommended for a tablespace to be made up of several (smaller) physical files if I have enough physical disk space for one large physical file ?
Thanks,
Gabriel

Answer 1

Hi,
The reason for having several datafiles on the server for a tablespace is the OS filesize limitation (typically like 2G on UNIX). Another reason is to be covenient
for portable tablespaces, and so on.
However, if you don't have OS limit (like Windows) then having one big tablespace is enough.
If you want to see the distributiion of datafiles run the following query first and then create your table and re-run the query again to see the file distribution.
select f.tablespace_name, d.file_name, sum(f.bytes) free_space_on_tbl
from dba_free_space f,
dba_data_files d
where d.FILE_ID = f.file_id     
group by f.tablespace_name, d.file_name;