RE: How to clear UNDOTBS

>> I have an UNDOTBS that is growin up.
>> How can I do to clear it ?

You don't have to. Try this:

select tablespace_name,status,count(*)
from dba_undo_extents
group by tablespace_name,status;

That will give you something like the following:

TABLESPACE_NAME STATUS COUNT(*)

UNDOTBS1          EXPIRED       310
UNDOTBS1          UNEXPIRED      81

As you can see, I have no ACTIVE undo extents, so the existing 391 extents, plus any free space in the tablespace are available for later use.

It's a bit like TEMP usage, when an extent is created, it lives on until you restart the database. The time saved by leaving it there against creating and deleting it when needed/finished with is obviously worth it.

>> I don´t need data that is there saved.
>> I can restart writting the UNDOTBS again.
If you *really* must, simply restart the database. Get all your users to log out etc, shut down any application still connected and restart the database.

However, Oracle will use existing EXPIRED extents when required, and if there are none, and no free space, it will start using UNEXPIRED ones. If there is free space then it will create new extents as it needs them.

Every time you restart the database, the UNDO tablespace will be cleared out, but as soon as your users start running transactions (that make changes) you will see extents being created and used and left behind.

You only need to worry about your UNDO tablespace if you don't have enough space and a transaction tries to create a new extent and there is no room. You don't worry about space used in the tablespace in any other situation and you don't need to reclaim it.

HTH Cheers,
Norman.

Information in this message may be confidential and may be legally privileged. If you have received this message by mistake, please notify the sender immediately, delete it and do not copy it to anyone else. We have checked this email and its attachments for viruses. But you should still check any attachment before opening it. We may have to make this message and any reply to it public if asked to under the Freedom of Information Act, Data Protection Act or for litigation. Email messages and attachments sent to or from any Environment Agency address may also be accessed by someone other than the sender or recipient, for business purposes. If we have sent you information and you wish to use it please read our terms and conditions which you can get by calling us on 08708 506 506. Find out more about the Environment Agency at www.environment-agency.gov.uk

Information in this message may be confidential and may be legally privileged. If you have received this message by mistake, please notify the sender immediately, delete it and do not copy it to anyone else.

We have checked this email and its attachments for viruses. But you should still check any attachment before opening it. We may have to make this message and any reply to it public if asked to under the Freedom of Information Act, Data Protection Act or for litigation. Email messages and attachments sent to or from any Environment Agency address may also be accessed by someone other than the sender or recipient, for business purposes.

If we have sent you information and you wish to use it please read our terms and conditions which you can get by calling us on 08708 506 506. Find out more about the Environment Agency at www.environment-agency.gov.uk

--
http://www.freelists.org/webpage/oracle-l