deallocate unused space on ora cle7

[tnabin]

please how to deallocate unused space of table on oracle 7.2 verson. can i use Alter tablespace "tablespace-name" coalesce in oracle 7. please tell me alternative of coalesce command

[jkoopmann]

wow, still using a 7.2 database, congratulations.

this answer is of course for you 7.2 database and what "coalesce" means in relation to that version.

coalesce works with unused/de-allocated space. basically what coalesce does is take adjacent unused segments in a tablespace and merges them together. your tablespace/data files will be the same size as when you begin.

to de-allocate space in a tablespace and giving back to the operating system, which is what i think you are asking, you need to use the ALTER DATAFILE RESIZE option. you can only resize / reclaim space at the end of the data file so if you have unused space in the middle of your data file it can only be reclaimed by reorganizing the objects in the tablespace, basically rebuilding them in a different tablespace that more suits the size you need.