Managing Storage Space
Reclaiming Wasted Space
Over time, updates and deletes on objects within a tablespace can create pockets of empty space that individually are not large enough to be reused for new data. This type of empty space is referred to as fragmented free space.
Objects with fragmented free space can result in much wasted space, and can impact database performance
The preferred way to defragment and reclaim this space is to perform an online segment shrink
Because a shrink operation may cause ROWIDs to change in heap-organized segments, you must enable row movement on the corresponding segment before executing a shrink operation on that segment. Row movement by default is disabled at segment level.
