Re: Don't understand ORA-01594/5

From: Brian Peasland <oracle_dba_at_nospam.peasland.net>
Date: Wed, 24 May 2006 18:03:35 GMT
Message-ID: <Izs7I7.L34@igsrsparc2.er.usgs.gov>

Terry Dykstra wrote:

> "Brian Peasland" <oracle_dba_at_nospam.peasland.net> wrote in message
> news:Izs27v.B7L_at_igsrsparc2.er.usgs.gov...

>> Terry Dykstra wrote:
>>> I'm using Netback to do a full backup of a 9205SE database and I get

> errors:


>>> ORA-01595: error freeing extent (2) of rollback segment (16))

>>>
>>> ORA-01594: attempt to wrap into rollback segment (16) extent (2) which

> is


>>> being freed

>>>
>>> I am using UNDO tablespace, so I'm confused by the suggestion in the

> manual:

>>> Action: The rollback segment shrinking will be rolled back by the

> system;


>>> increase the optimal size of the rollback segment.

>>>

>>> Should I drop the tablespace and create a new one using larger extents?
>>>
>> Are you sure that your UNDO tablespace is large enough for your
>> UNDO_RETENTION setting? Querying V$UNDOSTAT can show you if you are
>> stealing unexpired data, etc.
>>
>> HTH,
>> Brian
>>
>>
>>
>> --
>> ===================================================================
>>
>> Brian Peasland
>> oracle_dba_at_nospam.peasland.net
>> http://www.peasland.net
>>
>> Remove the "nospam." from the email address to email me.
>>
>>
>> "I can give it to you cheap, quick, and good.
>> Now pick two out of the three" - Unknown

> 
> All the xxxCNT columns have a value of zero.  The one exception is
> UNXPBLKREUCNT which has a value of 15 on 2 subsequent nights, 0 for all
> other nights.
> 

As shown in the Oracle docs, UNXPBLKREUCNT is the "Number of unexpired undo blocks reused by transactions". You never want to reuse, steal, or do anything with unexpired blocks in the UNDO tablespace. You may want to consider increasing the size of your UNDO tablespace. Or, you may want to lower your UNDO_RETENTION parameter. Query V$UNDOSTAT for the maximum MAXQUERYLEN value to find a good setting for UNDO_RETENTION.

HTH,
Brian

-- 
===================================================================

Brian Peasland
oracle_dba_at_nospam.peasland.net
http://www.peasland.net

Remove the "nospam." from the email address to email me.


"I can give it to you cheap, quick, and good.
Now pick two out of the three" - Unknown

Received on Wed May 24 2006 - 13:03:35 CDT