Understanding the Used (%) Column of the Tablespaces Summary report

Products

• Data Loss Prevention Enforce

Issue/Introduction

You want to understand the Used (%) Column of the Tablespaces Summary report in the Enforce Console.

Environment

DLP 15.x

DLP 16.x

Resolution

• The Used (%) of a tablespace is the proportion of the current tablespace size that has been allocated to segments - Used (MB) / Size (MB).
  • Once all of the allocated segments sizes within a tablespace reach the tablespace's Size (MB) value, that tablespace's Used (%) will be shown as 100. This doesn't mean that the segments themselves are fully occupied with data.
  • If a tablespace is unable to extend its size up to its maximum for any reason, such as insufficient drive space, you can have a situation where the Used (%) is 100 and the Size (MB) value is less than the Extendable To (MB) value.
  • Objects such as non-clustered tables, clusters and LOB columns each individually map to a single data segment in an Oracle database (not considering the partition case which is not supported in DLP).
• Once space has been allocated to a segment, that segment will not shrink even if data is deleted.
• Deleting data creates free space in segments that can be used for new data. The effect of data deletion is reflected in the % Full columns within the segment detail tabs, such as Incident Tables, Other Tables, Indices and LOB Segments.
  • Conversely, data deletion is not reflected in the Tablespaces Summary page in the Used (%) column for the reasons noted above.

Note:

• The Used (%) of a tablespace may be listed as 100%, but the segments within that tablespace may still have unused space. Just because the Tablespace Summary shows a specific tablespace at 100% does not mean that you must necessarily add more datafiles. First review the segment sizes and their % Full within the tablespace to determine whether additional datafiles are needed. System -> Database -> Table Details, review each tab on this page. You can sort by tablespace to group related segments.

 

Additional Information

See also: Extend Oracle tablespace (LOB_TABLESPACE, USERS, etc.) when almost full

See also: Why doesn't the database shrink after incidents are deleted?