Undo tablespace with active transaction/segment corrupted

How to recover if undo tablespace with active transaction/segment corrupted

Try RMAN blockrecover or restore the tablespace from latest backup and recover it.

Similar Messages

Cannot drop undo tablespace with Active extents but no active sessions

Hi all,
I am running on 10gr2 oracle database in a Linux 32 bit environment.
I have a corrupted undo datafile. I've been able to recover the datafile but still the alert logs is still showing that it is corrupted.
Now what I'm trying to do is to drop the old undo tablespace like the one discussed here Change undo tablespace in Oracle - Switch Oracle's Undo tablespace.
My problem is I have an Active extent but no active session corresponding to it:
SYS@ccasdb AS SYSDBA > SELECT a.name,b.status
FROM   v$rollname a,v$rollstat b
WHERE a.usn = b.usn
AND    a.name IN (
                  SELECT segment_name
                  FROM dba_segments
                  WHERE tablespace_name = 'UNDOTBS1'
                 ); 2    3    4    5    6    7    8
NAME                           STATUS
_SYSSMU18$                     PENDING OFFLINE
SYS@ccasdb AS SYSDBA > SELECT a.name,b.status , d.username , d.sid , d.serial#
2 FROM   v$rollname a,v$rollstat b, v$transaction c , v$session d
3 WHERE a.usn = b.usn
4 AND    a.usn = c.xidusn
5 AND    c.ses_addr = d.saddr
6 AND    a.name IN (
7               SELECT segment_name
8               FROM dba_segments
9               WHERE tablespace_name = 'UNDOTBS1'
10              );
no rows selected
but still cannot drop the undotablespace.
SYS@ccasdb AS SYSDBA > drop tablespace UNDOTBS1 including contents and datafiles;
drop tablespace UNDOTBS1 including contents and datafiles
ERROR at line 1:
ORA-30013: undo tablespace 'UNDOTBS1' is currently in use
Regards,
Tim

Yes i was able to recover the datafile but the alert_log kept on prompting that it is still corrupted. The datafile's status is online.
I want to kill the session/s contributing to the PENDING OFFLINE status of the rollback segment so I can already drop the undotablespace and so
that the alert log will stop prompting for that corrupted datafile in that UNDOTABLESPACE.
Can i Just alter the tablespace's datafiles to offline drop then just drop it. Then I drop the tablespace?

Growing UNDO datafile with small transactions?

Hi,
We're currently using 9i release 2 (with patchset) and have noticed that the UNDO datafile is increasing in size when it was my understanding that it shouldn't. We are performing a lot of DML (millions of inserts/updates) but commiting after each operation i.e. the transcations are very small but the number is very large. Why is the undo datafile getting very big in thos scenario and is there anything I can do to prevent it happening?
Many thanks,
Warren
[email protected]

After reading again ur post, i think my first answer is not adapted to ur question :-)
The Undo segment is a circular one so it will grow till he reached the last extent and after only re-write in the first one (if the undo-entries in the first extent are commited).
So the undo tablespace is too "big" in ur case cause u should have created it permitting it to grow big...
Fred

UNDO-Tablespace-Usage :: "ACTIVE" vs. "USED"

Hello,
when I run this
SELECT SUM(BYTES)/1024/1024/1024 "GB" ,STATUS
FROM DBA_UNDO_EXTENTS
GROUP BY STATUS;
against my database, I get this
MB STATUS
,008789063 UNEXPIRED
,094177246 EXPIRED
*19,7614746* ACTIVE
But when checking transactions with
SELECT s.sid , s.username , t.used_ublk*8/1024/1024
FROM v$transaction t
, v$session s
WHERE t.ses_addr = s.saddr;
I get this
SID USERNAME T.USED_UBLK*8/1024/1024
109 TRAM_STAT *6,0405426*
Where does this difference come from ???
Regards,
Mynz

ACTIVE: transaction running, still need for rollback
UNEXPIRED: transaction is not running, but still under UNDO_RETENTION period, so still needed.
EXPIRED: transaction is not running, not under UNDO_RETENTION period. When more extents will be needed for active, this extensts will be overwritten.
to check, how many undo are using a session, you can execute:
set pages 100 lines 160
col sid_serial for a20
col orauser for a15
col program for a30
col undoseg for a15
col undo for a10
SELECT TO_CHAR(s.sid)||','||TO_CHAR(s.serial#) sid_serial,
NVL(s.username, 'None') orauser,
s.program,
r.name undoseg,
t.used_ublk * TO_NUMBER(x.value)/1024||'K' "Undo"
FROM sys.v_$rollname r,
sys.v_$session s,
sys.v_$transaction t,
sys.v_$parameter x
WHERE s.taddr = t.addr
AND r.usn = t.xidusn(+)
AND x.name = 'db_block_size';

Executing transaction without active Undo Tablespace

Hi,
DB: 9.2.0.5
OS : AIX 5.2
I have opened my standby database in READ ONLY mode.I have undo tablespace.It is live setup and users are checking data with standby database.
SQL> show parameter aq_tm
NAME TYPE VALUE
aq_tm_processes integer 0
SQL>
SQL> show parameter undo
NAME TYPE VALUE
undo_management string AUTO
undo_retention integer 10800
undo_suppress_errors boolean FALSE
undo_tablespace string UNDOTBS1
SQL>
My standby alertlog getting warning message as
Mon Dec 13 12:16:39 2010
***Warning - Executing transaction without active Undo Tablespace
Mon Dec 13 12:27:37 2010
***Warning - Executing transaction without active Undo Tablespace
Mon Dec 13 12:28:03 2010
***Warning - Executing transaction without active Undo Tablespace
Mon Dec 13 12:28:17 2010
***Warning - Executing transaction without active Undo Tablespace
Mon Dec 13 12:34:43 2010
***Warning - Executing transaction without active Undo Tablespace
***Warning - Executing transaction without active Undo Tablespace
***Warning - Executing transaction without active Undo Tablespace
***Warning - Executing transaction without active Undo Tablespace
***Warning - Executing transaction without active Undo Tablespace
***Warning - Executing transaction without active Undo Tablespace
***Warning - Executing transaction without active Undo Tablespace
***Warning - Executing transaction without active Undo Tablespace
***Warning - Executing transaction without active Undo Tablespace
***Warning - Executing transaction without active Undo Tablespace
***Warning - Executing transaction without active Undo Tablespace
Mon Dec 13 12:35:22 2010
***Warning - Executing transaction without active Undo Tablespace
***Warning - Executing transaction without active Undo Tablespace
Please help me.
Thanks,
sunand

Hi Forstmann,
Thanks for your quick reply.
I have temp tablespace and see the below output.
SQL> select name from v$tempfile;
no rows selected
Which means i do not have any temp file to temp tablespace.
How do i can create tempfile in standby?.In what following states i can create,
1) MOUNT ( Recovery mode canceled)
2) READ ONLY
3) opened after FAILOVER
4) At any stage i can
My client is planning to check the DR server by doing FAILOVER.After that will create standby database again from primary.
Thanks,
Sunand

Rollback segments using UNDO Tablespace?

First, I created a database for a vendor with an Undo Tablespace UNDOTBS. Then the vendor requested me to create rollback segments instead. So I created a new tablespace RBSTBS just to hold these segments. When I tried to create the rollback segment using the newly created tablespace RBSTBS, it complained that I am not allowed to use non-system tablespaces.
So instead, I used the Undo tablespace UNDOTBS to hold the rollback segment. It worked.
Am I really allowed to use the UNDO tablespace to hold rollback segments? Can't I use normal tablespaces for rollback segments?
Another thing, the vendor wanted me to create rollback segments of 200MB each. Where do I set this while creating the rollback segment? Is this the INITIAL, NEXT, or OPTIMAL size?
I know that Oracle recommends using UNDO rather than rollback segments. Is there any advantage in using traditional rollback segments?
Thanks for any help!

Advantage with rollback segment is you can force your transaction to use any specific rollback segment, where as with undo you don't have any control. Oracle does it for us.
Thanks and Regards,
Satheesh Babu.S
Bangalore.

Undo Tablespace queries

Hi All,
I am bit confused with reading about the undo table space. so i need some clarification
1. There are 2 undo tablespace in our application. Could someone explain how the 2 undo tablespace works? I didn't find any details about this.
2. Both the undo tablespace is 100% utilized. Where the the new transaction will go? Will new transaction force the used blocks to be expired if needed?
3. What should be the ideal size of undo tablespace with respect to the total storage size?
4. is Archive log related to undotable space? if yes then When the archive logs get generated?
Thanks

1. In an RAC database, each Instance has to have it's own Undo Tablespace.
In a non-RAC (single instance) database, only one Undo Tablespace may be active at any time. The other Undo Tablespace would be inactive but can be switched to with an ALTER SYSTEM SET UNDO_TABLESPACE command.
2. Even if an Undo Tablespace is "100% used" Oracle can expire (and even drop) old extents and segments that are no longer needed by the Undo_Retention value. Thus, undo data for older transactions that have committed (more than Undo_Retention period has elapsed since the commit) will be overwritten.
3. There's no "ideal size". Undo sizing is based on Transaction volumes, fluctuations in transaction volumes, query patterns etc.
4. No, there is no direct relation between the two. However, all Undo that is generated also is written to Redo -- i.e. Redo captures Undo as well as it captures changes to Tables, Indexes etc.
I suggest that you read the Oracle Concepts documentation at
http://download.oracle.com/docs/cd/E11882_01/server.112/e16508/toc.htm
Hemant K Chitale
http://hemantoracledba.blogspot.com

(10gR2)Full UNDO tablespace

(10gR2)Full UNDO tablespace
============================
PURPOSE
10gR2 에서 UNDO tablespace 을 NO AUTOEXTEND로 생성한 경우 ,
transaction 이 실행중인 database 에서는 UNDO tablespace 가
FULL인 현상을 보게 됩니다.
이는 10gR2 에서 max retention 을 보장하는 undo retention 의
메카니즘이 소개되어 autoextend off 인 경우의 UNDO tablespace
에서 나타나는 현상입니다.
dba_undo_extents 에서 많은 UNEXPIRED undo segment 가 보이는 것이
확인되고 UNDO tablespace 가 100% full 인것처럼 나타나는 현상을 볼 수
있으며 그럼에도 불구하고 ORA-1555 나 ORA-30036 에러는 발생하지 않습니다.
Explanation
다음과 같이 많은 UNEXPIRED undo segment 가 조회됩니다.
SQL> select count(status) from dba_undo_extents where status = 'UNEXPIRED';
COUNT(STATUS)
463
SQL> select count(status) from dba_undo_extents where status = 'EXPIRED';
COUNT(STATUS)
20
SQL> select count(status) from dba_undo_extents where status = 'ACTIVE';
COUNT(STATUS)
21
dba_free_space 을 조회 결과 UNDO tablespace 의 free space 가 존재합니다.
SUM(BYTES)/(1024*1024) TABLESPACE_NAME
3 UNDOTBS1
58.4375 SYSAUX
3 USERS3
4.3125 SYSTEM
103.9375 USERS04
Transaction 이 실행되면 UNDO tablespace 에 free space 가 조회되지 않는
FULL 인것처럼 보입니다.
SUM(BYTES)/(1024*1024) TABLESPACE_NAME
58.25 SYSAUX
98 USERS3
4.3125 SYSTEM
87.9375 USERS04
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
다음은 AUM 에서의 Undo Block 할당 알고리즘은 다음과 같습니다.
1. current extent 에 free block 이 있으면 다음 free block 이
할당됩니다.
2. 그러나, free block 이 없으면, next extent 가 expired 되었다면 next extent 을
warp 한후 그 next extent 의 처음 block 을 return 합니다.
3. 만약 next extent 가 expired 되지 않았다면 UNDO tablespace 로부터 먼저
space 을 찾습니다. 이때 free extent 가 존재한다면 이를 transaction table 에
할당하고 해당 next extent 의 첫번째 block 을 return 합니다.
4. 만약 UNDO tablespace 에 free extent 가 없다면 offline 된 transaction table
에서 steal 합니다.
offline 된 transaction table 에서 extent 을 deallocate 한후 이를
current transaction table 에 add한후 그 add 한 extent 의 첫번째 free block 을
return 합니다.
5. offline 된 transaction table 에서 찾을수 없으면 , online 되어 있는
transaction table 에서 steal 합니다. offline 된 transaction table 에서 extent 을
deallocate 한후 이를 current transaction table 에 add한후 , 그 add 한 extent 의
첫번째 free block 을 return 합니다.
6. 1번~5번 까지 하여도 free block 을 얻지 못하면 이제 UNDO tablespace 의 file 을
extend 합니다.
file 이 extend 된다면 이후 current transaction table 에 extent 을 add 한후 ,
그 extent 의 첫번째 free block 을 return 합니다.
7. 6번 에서 UNDO tablespace 의 file 을 extend 하지 못했다면 , 자기의 transaction table
에서 unexpired 된 extent 을 재사용합니다. 그런데 이때 모든 extent 가 busy 하다면
즉 모두 uncommitted 된 정보라면 8번으로 갑니다. 아니라면 wrap 하여 unexpired 된
extent 을 사용합니다.
8. offline 된 transaction table 에서 unexpired 된 extent 을 steal 합니다. 이것이
실패한다면 online 된 transaction table 에서 unexpired 된 extent 을 steal 합니다.
9. 8 번까지 수행하고도 free block 을 얻지 못하면 이때서야 오라클에서는
"ORA-30036 unable to extend segment by %s in undo tablespace '%s' " 에러를
뿌리며 실패합니다.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fixed size UNDO tablespace 라 함은 autoextend 가 off 라 datafile 을 자동으로
더 이상 확장할 수 없음을 말합니다.
autoextend 가 off 인 경우 10.2 부터는 max retention 이 36 시간 입니다.
undo_retention 을 900 초(15 분) 으로 설정을 한다고 해도 10gR2 에서는
max retention 이 36 시간이라 이에 해당하는 undo extent 을 UNEXPIRED 으로 만듭니다.
그러나 이것이 가용한 undo extent 가 없다는 것이 아니고 , transaction 이 실행되게 되면
UNEXPIRED undo segment 을 재사용하게 됩니다.
References
< Note 413732.1 - Full UNDO Tablespace In 10gR2 >

A undo tablespace almost full is not necessarily a problem with Oracle 10g ... unless you have some ORA-XXXX errors in the database instance alert.log or in client programs connected to the instance. Is this the case ?
You should also have a look to V$UNDOSTAT which stores undo statistics for the last 7 days.
This view has also 2 interesting columns about possible errors related to undo space:
SOLDERRCNT NUMBER Identifies the number of times the error ORA-01555 occurred. You can use this statistic to decide whether or not the UNDO_RETENTION initialization parameter is set properly given the size of the undo tablespace. Increasing the value of UNDO_RETENTION can reduce the occurrence of this error.
NOSPACEERRCNT NUMBER Identifies the number of times space was requested in the undo tablespace and there was no free space available. That is, all of the space in the undo tablespace was in use by active transactions. The corrective action is to add more space to the undo tablespace.

Drop Undo Tablespace taking more than 1 hr

Hi,
To give you background, I had given an "insert into .. select" command which was inserting 3 millions of rows of rowidth approx 5000 bytes. The window on which it was given, was closed by mistake.
After sometime when I checked the size of undo_tablespace, it was 5.5GB. I decided to create a new one and drop the old undo_tbsp.
I have successfully created new undo tablespace and changed the same in spfile also.
now when i am dropping the old undo tablespace, its taking long time. its almost an hour, but the tablespace has not been dropped yet.
I have given following command
drop tablespace undotbs_01 including contents;
Any idea, why is it taking so much time, and how long should I wait?
If someone can give me any other idea on how can I drop the tablespace, that will be great.
Regards,
Archana.

To give you background, I had given an "insert into .. select" command which was inserting 3 millions of rows of rowidth approx 5000 bytes. The window on which it was given, was closed by mistake.This could be the cause.
I wonder the killed/closed session doesn't hangup with a latch or lock.
Since the old undo tbs had active transaction, it might have to pending offline status. If so, you can drop it.
Jaffar

How to drop an undo tablespace which is in Pending Offline status

Dear All,
I changed my undo tablespace from undotbs1 to undonew in order to drop undotbs1.
But my undotbs1 is in pending offline state, how can i drop undotbs1
Thanks
Mahi

Check here
Managing the Undo Tablespace
Query V$TRANSACTION find out which transaction holding rollback segment on old undo tablespace. Commit or rollback it.
Or simply wait for a while patiently.
Quote "
The switch operation does not wait for transactions in the old undo tablespace to commit. If there are any pending transactions in the old undo tablespace, the old undo tablespace enters into a PENDING OFFLINE mode (status). In this mode, existing transactions can continue to execute, but undo records for new user transactions cannot be stored in this undo tablespace.
An undo tablespace can exist in this PENDING OFFLINE mode, even after the switch operation completes successfully. A PENDING OFFLINE undo tablespace cannot be used by another instance, nor can it be dropped. Eventually, after all active transactions have committed, the undo tablespace automatically goes from the PENDING OFFLINE mode to the OFFLINE mode.
"

Can UNDO tablespace be locally managed?

I read in the Oracle 9i Administrators guide that the SYSTEM tablespace can ONLY be dictionary managed. You do not have the option of having it locally managed. Is this the same for the UNDO tablespace? I couldn't find it anywhere in the Admin guide, one way or the other.
Michael

UNDO_TABLESPACE
Parameter type
String
Syntax
UNDO_TABLESPACE = undoname
Default value
The first available undo tablespace in the database.
Parameter class
Dynamic: ALTER SYSTEM
Range of values
Legal name of an existing undo tablespace
Real Application Clusters
Multiple instances can have different values.
UNDO_TABLESPACE specifies the undo tablespace to be used when an instance starts up. If this parameter is specified when the instance is in manual undo management mode, an error will occur and startup will fail.
If the UNDO_TABLESPACE parameter is omitted, the first available undo tablespace in the database is chosen. If no undo tablespace is available, the instance will start without an undo tablespace. In such cases, user transactions will be executed using the SYSTEM rollback segment. You should avoid running in this mode under normal circumstances.
You can replace an undo tablespace with another undo tablespace while the instance is running.
See Also:
Oracle9i SQL Reference.
http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96536/ch1218.htm#REFRN10227
http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96540/toc.htm
Joel P�rez

Undo Tablespace and Temporary Tablespace - autoextend ?

- In general, should I allow the Undo Tablespace to grow (autoextend)?
- In general, should I allow the Temporary Tablespace to grow (autoextend)?

The size of undo tablespace should always keeps in mind otherwiase you eill get ORA-1555 or out of space errors.
This paper is to help DBA’s in calculating the size of UNDO tablespace by using a simple formula.
It is tough to know about the number of transactions and subsequently number of rows changed per second.
So I suggest having a “big undo tablespace” to start with and based on load, after doing some calculations and resize your UNDO tablespace.
In my case one of the applications was going to production (live), and I had no idea that how many transactions will happen against this database. All what I was told that there will be optimum (transactional) activity on this database.
So I started with UNDO tablespace with size of 3GB and datafiles with autoextend “on” .
Note:
In production, you must be very careful in using this (autoextend on) as the space may grow to inifinity very fast. So my advice is either dont use this option, or use with "maxsize" or continuously monitor space (which is tough).
I month later, I noticed the activity from V$undostat.
Here is the step by step approach:
Step 1: Longest running query.
SQL> select max(maxquerylen) from v$undostat;
MAX(MAXQUERYLEN)
1793
This gives you ideal value for UNDO_RETENTION. To be on the safer size you should add few more seconds to get the right value. So in my case, the size of undo retention should be say 2000 secs.
Step 2: Size of UNDO tablespace.
Size of UNDO needed = UNDO_RETENTION x [UNDO block Generation per sec x DB_BLOCK_SIZE] + Overhead(30xDB_BLOCK_SIZE)
Out of these we know UNDO_RETENTION and DB_BLOCK_SIZE
All we need is to find out “UNDO Blocks per second”
Which can be easily fetched from v$undostat
SQL> SELECT (SUM(undoblks))/ SUM ((end_time - begin_time) * 24*60*60) "UPS"
2 FROM v$undostat;
UPS
8.11985583
V$undostat stores data for every 10 mins and begin/end times are start/end time of those intervals. We multiplied it with 24*60*60 because the difference between two dates will be in days and to get to seconds, we need it to multiply with 24hrs*60mins*60secs
So now we have all the values needed.
Undo size needed = [8.12 x 2000 x 8192] + [30 x 8192] = 133283840 bytes = 127.11 MB

Is there so call "dedicated" UNDO tablespace in Oracle 9i and higher?

Since one of our applicaions needs to process large amounts of data, we have been using a dedicated rollback segment in order to avoid the "snapshot too old" problem.
Recently our DB upgraded to Oracle 9i and DBA asked us to use "undo" tablespace.
Based the Oracle 9i Doc., it only allows to select ONE undo tablespace at a time.
If so, DBA has to make the only UNDO as large as our Cash large transactions
need(adjust the UNDO_RENTION), which inevitably waste lots of space.
Does Oracle 9i allow to have one dedicated UNDO tablespace for large transactions while another one for regular transactions just like we use the old rollback segments.
Thanks in advance

Why have multiple UNDO tablespaces? You can only use one at a time, and when the other one is not being used, it still consumes storage space.
Spend a little time determining how much undo you need and size undo tablespace and undo retention around those values and you should be able to resolve the problems you are experiencing now.
http://download-east.oracle.com/docs/cd/B10501_01/server.920/a96521/undo.htm#9505

FLASHBACK OFF FOR UNDO TABLESPACE????

Hi all
As my Undo tablespace growing evryday 2 GB & NOW it reached 19,
Database size is 6GB only
using Oracle 10g Release 2 without patch Set (release 1002000100) on Hp-Unix OS
Can i use the Undo tablespace with FLASHBACK OFF option?
what are the Consequences for Turning off the FLASHBACK,
Can we use this type of Undo tablespace with Flashback OFF???
CREATE UNDO TABLESPACE UNDOTBS03 DATAFILE
'/app/oracle/product/oradata/prod/undotbs03.dbf' SIZE 1000M AUTOEXTEND OFF
ONLINE
RETENTION NOGUARANTEE
BLOCKSIZE 8K
FLASHBACK OFF;
THANKS ALOT

Oracle Flashback Database: feature is similar to conventional point-in-time recovery in its results, allowing you to return a database to its state at a time in the recent past. It is, however, much faster than point-in-time recovery, because it does not require restoration of datafiles from a backup and it requires application of fewer changes from the archived redo logs.
UNDO Tablespace: Oracle db save the old value when a process change data in undo tablespace.
I think that you can change de default UNDO tablespace as NO AUTOEXTEND, and
Configure
SET UNDO_MANAGEMENT=AUTO
SET UNDO_RETENTION= ( second need for logger transaction )
UNDO_RETENTION specifies (in seconds) the low threshold value of undo retention. For AUTOEXTEND undo tablespaces, the system retains undo for at least the time specified in this parameter, and automatically tunes the undo retention period to satisfy the undo requirements of the queries.
For fixed- size undo tablespaces, the system automatically tunes for the maximum possible undo retention period, based on undo tablespace size and usage history, and ignores UNDO_RETENTION unless retention guarantee is enabled.

Recreation of undo tablespace

hi
i'm using oracle 9i.whether frequent recreation of undo tablespace is essential.
if yes then what is the purpose
regards

There could be adhoc scenarios when re-creating simplies houskeeping work.
Say you have a day to day application which needs 4GB of undo and your undo tablespace is 5gb. The application will run without any issues. After 3 months say you a quarterly closure or financial year closure and you need to run heavy batch jobs certain other heavy dmls on database and you really dont know how much undo is needed in excess. You simply add further 4gb or leave the datafile to autoextned on to prevent your batch jobs from failing.
After a week your finacial closure is over, undo tablespace has grown to 10GB and for next 3 month you are not going to run that batch job and you will happy with 4gb of undo space.
In such scenario, if you want to release the 6 gb back to operating system , the simple way is to create new undo tablespace with 5gb and make it current and drop the old one.
Hope this explains...

Undo tablespace with active transaction/segment corrupted

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