One of the important DBA tasks is to watch the storage usage of all the tablespaces to make sure there are enough free space in each tablespace for database applications to function properly. Free space information can be monitored through the USER_FREE_SPACE view. Each record in USER_FREE_SPACE represents an extent, a contiguous area of space, of free space in a data file of a tablespace.

Here is SQL script example on how to see free space of a tablespace:

SQL> connect HR/globalguideline

Connected.

SQL> SELECT TABLESPACE_NAME, FILE_ID, BYTES

2 FROM USER_FREE_SPACE

3 WHERE TABLESPAE_NAME IN ('USERS', 'MY_SPACE');