Question regarding lob column

  • From: Maureen English <sxmte@xxxxxxxxxxxxxxxx>
  • To: oracle-l-freelists <oracle-l@xxxxxxxxxxxxx>
  • Date: Wed, 06 May 2009 12:56:08 -0800


We have a table that has a lob column.  The table is in tablespace A, the lob 
storage is
in tablespace B (with an associated index).

Every month a job runs and adds more data to this table, so we've had to add 
on a regular basis.  Now the user wants to delete some data so we don't have to 
adding datafiles, but can reuse some of the space that's already been allocated 
to the

So, I got a rowcount from the table before the user deleted anything, and I 
also got the
bytes and extents values from dba_segments for the tablespaces.

The user then proceeded to delete at least 1/3 of the rows in the table.  When 
I did my
queries again, the rowcount had changed as expected, but the bytes and extents 
didn't change for the segments in dba_segments.  There were 172 extents before 
and there
are 172 extents after the delete.

Any ideas as to why no extents appear to have been freed up?

We don't have Grid Control or EM available, so I can't see any pictures of 
space usage....

- Maureen


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