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Re: "Deallocate Unused" not releasing space above HWM

From: Ron Rogers <RROGERS_at_galottery.org>
Date: Wed, 10 Mar 2004 10:05:51 -0500
Message-Id: <s04ee892.092@galottery.org>


Mladen,
 You are 100% correct in you statement about reclaiming the unused space. I would also suggest that the data be exported before the truncation followed by an import or you can practice the recovery policy that you have established.
Ron

>>> mladen_at_wangtrading.com 03/10/2004 9:35:15 AM >>> On 03/10/2004 07:27:43 AM, vidya kalyanaraman wrote:
> 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 dba_tables.
> 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.

Strictly speaking "deallocate unused" is not supposed to change the HWM. Truncate is.
Truncate your tables and HWM will be moved back. Way back.



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Received on Wed Mar 10 2004 - 09:16:40 CST

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