Extent Deallocation
722733Jan 20 2010 — edited Jan 20 2010Hi Everyone,
I have a scenario- DATABASE 11g Release 2, Table FRAG with uniform extent allocation size 10m and initial extent 1, upon some huge inserts the extents are 3 and after some time, huge deletes are performed on the table, which now contains only few rows, say 10% of actual rows before deletion. And I issued
ALTER TABLE FRAG DEALLOCATE UNUSED;
After querying the data dictionary views I found that the extents allocated are still the same which are 3, can someone please explain how the extents are deallocated, I know that when the schema object is dropped or when the table is truncated and even segment shrink functionality which was introduced in 10g will deallocate the extents. But how about the sql statement I issued above (ALTER TABLE FRAG DEALLOCATE UNUSED) does it not deallocate the extents. Thanks in advance for your help.