Freespace Statistics 

Select Freespace and fragmentation of all tablespaces.

With these statistics you can see whether it is necessary to extend a tablespace or whether a reorganization should be performed instead or in addition. Check the following information:

When the utilization is more than 90 percent, you should extend the tablespace by adding a new data file.

Please do not try to solve this problem by reorganizing the database. A reorganization defragments the complete storage space. This means that the fragmented used storage space and fragmented free storage space are put together, i.e., the storage space is reorganized, but no additional space is gained by this. In fact, additional space may even be required. Therefore, always extend a tablespace where there is little space left.

If the percentage of the storage space used is relatively low, you should check these columns to see whether the storage problems in a tablespace are due to the fragmentation of free storage space.

If the number of fragments is high and the largest fragment is small (smaller than 1 MB), the cause of the tablespace overflow is probably the fragmentation. It may be useful to reorganize the fragmented tablespace (or highly fragmented tables and indexes in it) instead of extending it. However, please note: Since enough data files are available, you can solve this problem by adding a new file. If possible, avoid reorganization because it is more complicated and time-consuming.