Hello DBAs,
I was reading oracle doc "https://docs.oracle.com/cd/E18283_01/server.112/e17120/schema003.htm and have confusion on this point :-
Segment shrink reclaims unused space both above and below the high water mark. In contrast, space deallocation reclaims unused space only above the high water mark.
1. How Segment shrink reclaims unused space both above and below the high water mark because space above high water mark will already used ?
2. Is space de-allocation different from shrink operation because its mentioned that during shrink operations, by default, the database compacts the segment, adjusts the high water mark, and releases the reclaimed space ?
3. I am thinking that space de-allocation and release reclaimed space are same thing ?
Please help me to understand this concepts
Thanks