TABLESPACE cleanup not happening after table data delete

Question

Hi all
I have a partitioned table with 4 partitions all residing in a single tablespace. I populated the table with sample data and then deleted all with a simple delete statement followed by a commit. But the tablespace is still showing data from the 4 partitions under the bytes column in query below:
select segment_name, partition_name, tablespace_name, bytes
from dba_segments
where tablespace_name='tb_name'
Am I missing something here? Do I need to run some other command after delete and commit to fully flush out the data?
FYI, my system specs are:
Windows 2008 Server Standard (32-bit)
ORACLE 11.1.0.7.0

Answer 1

HI,
LMT is Locally Managed Tablespace.
+Moreover, when you say the blocks will not be available immediately when do you reckon they will be available? How do I go about automating this to free up space as soon as data is deleted?+
You cannot automate this job, this is already automated by Oracle.
+FYI, both pct_free and pct_used come up as empty values for my table.+
reason for a NULL-value for PCT_USED is that the tablespace where the table resides uses automatic segments space management (ASSM). With ASSM there is no need for PCT_USED only for PCT_FREE. Oracle manages blocks automatically.
You dont worry about releasing the space, Oracle will take care of it automatically.
Go through the below link
[http://download.oracle.com/docs/cd/B19306_01/server.102/b14231/tspaces.htm#ADMIN10065]
[http://download.oracle.com/docs/cd/B19306_01/server.102/b14231/schema.htm#sthref2100]
[http://www.dba-oracle.com/art_builder_assm.htm]
This is an extract form Oracle docs
Understanding Reclaimable Unused 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. This process consolidates fragmented free space below the high water mark and compacts the segment. After compaction, the high water mark is moved, resulting in new free space above the high water mark. That space above the high water mark is then deallocated. The segment remains available for queries and DML during most of the operation, and no extra disk space need be allocated.
You use the Segment Advisor to identify segments that would benefit from online segment shrink. Only segments in locally managed tablespaces with automatic segment space management (ASSM) are eligible. Other restrictions on segment type exist. For more information, see "Shrinking Database Segments Online".
If a table with reclaimable space is not eligible for online segment shrink, or if you want to make changes to logical or physical attributes of the table while reclaiming space, you can use online table redefinition as an alternative to segment shrink. Online redefinition is also referred to as reorganization. Unlike online segment shrink, it requires extra disk space to be allocated. See "Redefining Tables Online" for more information.Regards,
Vijayaraghavan K