Re: Online "tablespace" reorg ?
- From: <rjsearle@xxxxxxxxx>
- To: maxim.pakhutkin@xxxxxxxxxx
- Date: Thu, 30 Jun 2005 10:37:27 +1000
The closest we've come to here (8.1.7, Solaris (no partitioning) is to use
Materialized Views (MVs). This method effectively allows a table to be
rebuilt, reclaim unused space (left over from archiving) There is minimal
downtime while the tables are renamed and grants established. We use this
method repeatedly and have reclaimed over 100G os valuable space in an DSS
env and halved table scan times.
We got the idea from askTom.
If you do this for each table in the tablespace, you will achieve a
rebuild. This method is time consuming however it is better than nothing as
the tables remain online and the indexes remain valid for the duration of
the rebuild. You will need sufficient additional disk space to maintain a
duplicate of the table and the indexes. Once a new version has been built
then the old version can be dropped
HTH
Russell
On 6/30/05, Pakhutkin, Maxim (Max) <maxim.pakhutkin@xxxxxxxxxx> wrote:
>
> 10g OEM (Grid Control) appears to do online tablespace reorgs by means of
> generating a whole lot of code to perform dbms_redef and all the attending
> actions for all the objects in the tablespace. So you could conceivably
> generate such a script (without running it) via OEM on a test database, save
> it to a file, run it on test and then run it on your production system.
> First thing OEM will do is scan for objects that cannot be online redefined
> with dbms_redef. It will also tell you to set up an external proc for
> handling LONGs if you don't already have one setup. I wouldn't trust OEM to
> do it unsupervised even on a test system, though, at this point, as I've
> seen errors even on "successful" online table reorgs performed by it. I'm
> still researching it though, haven't run any tablespace reorgs yet.
>
> Max Pakhutkin
>
> -----Original Message-----
> From: oracle-l-bounce@xxxxxxxxxxxxx
> [mailto:oracle-l-bounce@xxxxxxxxxxxxx]On Behalf Of Bob
> Sent: Tuesday, June 28, 2005 5:54 PM
> To: oracle-l@xxxxxxxxxxxxx
> Subject: Online "tablespace" reorg ?
>
>
> All-
> Is there such a thing as online tablespace reorg?
>
> All, I've been tasked to perform an "online reorg of our tablespaces"
> From my research I come to these findings.
>
> 1 - tablespace reorg is not a popular topic and only seems to be available
> using oem which due to our diverse environment, I need to use a
> sqlplus script. From reading ask tom he is claiming there really isn't
> anything to "reorg" in a tablespace - recreate yes - reorg no
> Is this correct?
>
> 2 My plans would be to create new tablespaces using LMT and ASSM, then
> alter
> table move .. new tablespace. The LMT would minimizes future fragmentation
> and ASSM would benefit by using the alter table shrink; statement to alter
> the HWM in the future.
>
> Questions,
> 1 - Is there such a thing as online reorg of tablespaces and if so
> documentation on its use?
> 2 - Are there any issues that I'm overlooking in item 2
>
>
> Thanks
> Bob
>
> side note -dbms_refefination looks like what I've been told to look for
> but
> that is on the table level and not going to help because the tablespaces
> are DMT. I don't need to redef the tables I'm really looking to reclaim
> space from the tablespaces as well as putting the tables in LMT and ASSM
> mode
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