RE: "Deallocate Unused" not releasing space above HWM

  • From: <k.sriramkumar@xxxxxxxxxxxxxxxxxx>
  • To: <oracle-l@xxxxxxxxxxxxx>
  • Date: Wed, 10 Mar 2004 18:18:56 +0530

Hi Vidya,

        I thought Deletes happen within the HWM....I am confused by your 
statement "deletes above the HWM".....Guru's pls correct me if I am wrong.

Best Regards

Sriram Kumar

-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On 
Behalf Of vidya kalyanaraman
Sent: Wednesday, March 10, 2004 5:58 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: Re: "Deallocate Unused" not releasing space above HWM

Hi All
 I am trying to reclaim the wasted space (huge deletes), which are above the 
HWM.  I had analysed the table before and got the "empty_blocks" details from 
I am using the following query,
 alter table tab1 deallocate unused;
and then to bring down the HWM,
alter table tab1 move tablespace AR_DATA;  ---- Moved within the same tablespace
and then I had rebuilt all the corresponding indexes.
As a last step, I had coalesced the tablespace.
Next day (because SMON is not going to clear it up immediately), I had analyzed 
the tables again and got the "empty_blocks" details from dba_tables.
When I look the empty_blocks, for some tables it has not yet released the 

Am I missing  any steps?  I searched Metalink, but it looks like I have covered 
everything that needs to be.
I have one more question. To really reclaim the space, do I have to move the 
table out of its own tablespace ?
Any thoughts are most welcome.

Thanks and Regards

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