Undo tablespace increasing

hello
my database version is 11.2.0.1.0
My undo tablespace was around 36 gb and around 4gb was free.
But now the size is decreasing and it is decreasing fast. What should i do. I increased it by another 2gb. How do i monitor it so that i can tune it without resizing it again.
please guide me.
Thanks in advance.

user12045405 wrote:
hello
my database version is 11.2.0.1.0
My undo tablespace was around 36 gb and around 4gb was free.
But now the size is decreasing and it is decreasing fast. What should i do. I increased it by another 2gb. How do i monitor it so that i can tune it without resizing it again.
please guide me.
Thanks in advance.Decreasing or increasing? It's not an issue but a normal thing since 10g onwards. Please see MOS Doc 413732.1 .
HTH
Aman....

Similar Messages

UNDO tablespace increase more more .... spaces

I checked my Oracle database. I found undo tablespace increase more more spaces.
from 10G , now 40G
undo_retention = 15 minutes
Please help me
How I tune and monitor for track this problem?

Hello HunterX,
You have not indicated which version of database & on what platform. The Version number & platform is very important...I tell you why. Because i had the same issue with my database and handled successfully.
Please check the BUG No. Note:2660394.8 & also note no. 271119.1.
This explains that Undo tablespace is used and after the expiry of 15 minutes it does not use the EXPIRED extents. It again allocates the NEW extents out of your segment of the tablespace....And leads to continuous growing of UNDO Tablespace...
Do the follwoing i feel would be appropriate...Rest you can decide it better....
1. Create a New UNDO Tablespace may be undo_new of smaller size..
2. Do not keep autoextend ON and put some max size...may be 1 GB. Do not put it unlimited.
3. Stop the DB Instance
4. Change the name of new UNDO Tablespace in INIT.ORA file
5. Restart the DB Instance.....
6. drop the Old Tablespace UNDO & delete the datafile...
If stopping of DB Instance is not possible...(for production server), i hv few command which does the above on-line. But i do not remember them at this time...I will hv to refer my docs. If you feel i can try that for you...otherwise you may follwo above points.
Hope that helps to you. Thanks.
Regards,
Kamesh Rastogi

Undo Tablespace - Huge file growth.

Hi,
My undo tablespace increases in size rapidly. We have to perform huge number of update operations in this database. How can I reduce the size of the undo tablespace on a regular basis?
Regards,
Santhosh

There is known bug in prior 9.2.0.5 releses . Undo tablespace does not use expired extents properly if it can allocate new segment. Upgrade to 9.2.0.5 is regular solution. Workaround is seting undotablespace autoextend off.
ciaos
Srdjan Rasulic

Regarding Maxsize of Undo Tablespace

Dear expetrs
While executing a procedure i got error.
Error In Insertion..ORA-30036: unable to extend segment by 16384 in undo tablesp
ace 'UNDOTBS1'
then i increase the size of the Undo Tablespace
then again i got error.
ORA-01144: File size (7680000 blocks) exceeds maximum of 4194303 blocks
plz give me answer as soon as possible.
thnaks.

1) resize your datafile to 4194303 * db_block_size
alter database datafile < path/filename > resize <4194303 * db_block_size> ;
you find db_block_size by:
sqlplus /nolog
SQL> connect / as sysdba
SQL> show parameter db_block_size
or by simply have a look in the pfile (init<SID>.ora) in $ORACLE_HOME/dbs
2) add another file to the undo tablespace:
SQL>alter tablespace undotbs1 add datafile <path/filename> size <n> M;
a tablespace may have up to 1022 datafiles.
hope this helps
roman

Problem with UNDO tablespace

Hi guys.
Our database has 50GB of undo tablespace. I decided to create a second undo tablespace and switch to the new one. Since doing that yesterday, the size of the old undo is 49GB (was thinking that the values will drop to zero) and the new tablespace keeps increasing in size! Its size now is about 20GB. I do have the following question.
a) If I restart the database, it the value of the old undo going to fall to zero?
b) undo_retention=86400. Setting this value to a lesser value say 800seconds, it is going to act the performance of the database? Is it going to release the space on the old undo?
Thanks and any help is appreciated.
David

The undo tablespace will not automatically shrink size, since you have a new undo tablespace in place. You can drop the old one if you don't plan to use it.
Set lower undo_retention will certainly help to contain the undo space usage. However you should query v$undostat and v$rollstat to estimate the amount of undo space required for the current workload then size the undo tablespace accordingly. Turn off the auto extend on undo tablespace.

Undo tablespace keeps on growing

We have a 3rd party application running on our oracle(10.2.0.4) database running on 64bit solaris(sparc) machine.
Since few days my undo started going up. I increased the size from 2g to 5g. Still it is at more then 90%levels.
I ran this query to see which session is using maximum undo
SELECT a.sid, b.name, a.value
FROM v$sesstat a, v$statname b
WHERE a.statistic# = b.statistic#
AND a.statistic# = 176
ORDER BY a.value DESC
From this i found the session which is using max undo.
When i query this sid from v$session i see this is inactive
my undo retention is set to 9000 and undo management is auto
how can i check if i have expired undo blocks that are not being used

>
Since few days my undo started going up. I increased the size from 2g to 5g. Still it is at more then 90%levels.
I ran this query to see which session is using maximum undo
SELECT a.sid, b.name, a.value
FROM v$sesstat a, v$statname b
WHERE a.statistic# = b.statistic#
AND a.statistic# = 176
ORDER BY a.value DESC
From this i found the session which is using max undo.
When i query this sid from v$session i see this is inactive
my undo retention is set to 9000 and undo management is auto
>
With an UNDO_RETENTION of 2.5 hours set, I am not surprised that you use up to (or even more than) 5g space in the UNDO tablespace! I would even call that moderate.
What is your concern? If you don't have the space for your UNDO tablespace, lower UNDO_RETENTION accordingly. Notice that UNDO_RETENTION is the wish to preserve before images for that long time even if their transaction did already commit. Why have you set it to that (relatively high) value of 2.5 hours?
Kind regards
Uwe
http://uhesse.wordpress.com

UNDO Tablespace size

Hi,
We have a production database with size 120GB (DB Version 11.1.0.6), And our UNDO Tablespace size is 30GB.
For the past 4 days the UNDO tablespace utilization is more than 85%.
We have disabled the AUTOEXTEND for the UNDO Tablespace.
So the UNDO RETENTION is dynamically calculated by Oracle itself and the value now is
TUNED_UNDORETENTION
339183
Please suggest how to fix this issue.
Thanks !

Hi,
The UNDO Tablespace size is still increasing. We dont have flashnack enabled for our database.
The database is 11.1.0.6 Standard Edition.
TABLESPACE TOTAL_SIZE_IN_MB FREE_SPACE_IN_MB % FREE %USED
UNDOTBS1 32152 4440 14 86.19
USERS 123784 23120 19 81.32
SYSTEM 1536 465 30 69.73
SYSAUX 1024 449 44 56.15
GGS_DATA 2048 1388 68 32.23
We enabled AUTOEXTEND on for one of the datafiles in UNDO Tablespace.
NAME TYPE VALUE
undo_management string AUTO
undo_retention integer 9000
undo_tablespace string UNDOTBS1
select to_char(begin_time, 'DD-MON-RR HH24:MI') begin_time,
to_char(end_time, 'DD-MON-RR HH24:MI') end_time, tuned_undoretention
from v$undostat order by end_time;
BEGIN_TIME END_TIME TUNED_UNDORETENTION
23-DEC-11 18:15 23-DEC-11 18:25 375077
23-DEC-11 18:25 23-DEC-11 18:35 375678
23-DEC-11 18:35 23-DEC-11 18:45 376278
23-DEC-11 18:45 23-DEC-11 18:51 376578
Please let me know how can i reduce the space consumed by UNDO Tablespace.

Undo Tablespace

Hi,
For one of the database, Undo tablespace has reached upto 2.5GB. I have created one more undo tablespace. If users are frequently commiting the transactions, why it is increasing. It is a development database.
Can I delete the undo tablespace, once I conclude that the transactions are using the new undo tablespace?
Pls guide me.
Thanks,
Raj

Hi,
Before going to recreate the undo tablespace calculate the optimal sizing undo and create make changes as per nedd.
Read below post.... This may helps you....
Undo growth
Regards,
Karthik

Undo tablespace utilizes 100 %

hi,
We are using oracle 11.2.0.3.0 on solaris 10 sparc 64 bit. From last week we are facing an issue our undo tablespace got 100 % full , we have add the data files and increase the size upto 300 gb. But after some time it utilizes all the available space and cant release it.
Thanks

user11062519 wrote:
hi,
We are using oracle 11.2.0.3.0 on solaris 10 sparc 64 bit. From last week we are facing an issue our undo tablespace got 100 % full , we have add the data files and increase the size upto 300 gb. any long running batch jobs configured ?what is your undo retention period?
But after some time it utilizes all the available space and cant release it.space cannot release until unless active transaction ends.

Doubt regarding ORA-30036: unable to extend segment by 8 in undo tablespace

I am using 11g Release 1 Database .
I have to analyze the performance of two tables of different designs which serve the same purpose and come up with the design which is efficient .
SQL> desc staging_dict
Name                                      Null?    Type
SNO                                                NUMBER
CODE_FRAGMENTS                                     CLOB
CODE_FRAGMENTS_U                                   CLOB
CODE_FRAGMENTS_D                                   CLOB
CODE_FRAGMENTS_DO                                  CLOB
SQL> desc staging_dict1
Name                                      Null?    Type
SNO                                                NUMBER
CODE_FRAGMENTS                                     CLOB
CODE_FRAGMENTS_UD                                  CLOB
CODE_TYPE                                          VARCHAR2(5 CHAR)Initially I tried inserting a few thousand records into both the tables . Then I did some conversion on one column and I populate the result on other column of the same table . So I update the table in bulk mode and I commit for every thousand records .
I have a undo tablespace of 2G with undo_retention=900 , retention guratantee is not set for the undo tablespace .
When I tried the conversion and update on the first table (STAGING_DICT) it took more time for around 2500 records compared to other table and when I increased the number of records to 10000 it threw an error
ORA-30036: unable to extend segment by 8 in undo tablespace 'UNDOTBS'
But I didn't come across this error when I tried the conversion and update on the table for the same 2500 records (STAGING_DICT1) and it was also 10 times faster .
My doubt is does the error ORA-30036 occur because it is saving the undo image of all the four clob columns though I am doing conversion on one column and updating the other column (using only two columns in the update and only one column is affected by update command) ?
Also how is that having less CLOB rows prove more effective by adding one more VARCHAR column which differentiates the code_frament type in the STAGING_DICT1 table than having it as more CLOB columns as in STAGING_DICT table ?

Don't you think the error OP reported is kind of weird?
Because as you said, Oracle stores "undo" of lob in user tablespace not undo tablespace if the lob is stored out-of-line.
1. If the size of lob was small, small size of undo would be stored into undo tablespace,
and OP would'nt have undo tablespace shortage problem.
(How does small lob flood undo tablespace?)
2. If the size of lob was big, OP would have 01555 error on user tablespace not undo tablespace shortage error.
So, i think there are 2 theories that can explain this abnormality.
1. OP hit the bug of massive undo generation.
2. OP is using securefile which is 11g new feature.
Oracle documents says that undo for securefile lob is stored in "undo" tablespace, not user tablespace.
But unfortunately, i'm not sture about this coz i didn't try it myself

How to reduce the size of UNDO tablespace?

Hello,
I was doing client copy from my production system to quality for which I increased
the UNDO tablespace.Now i want to reduce the size of UNDO tablespace so that i can use the
free space for other purpose.
Thanks in advance

[Here we go!|Procedure to delete and create PSAPUNDO;
Reagrds,

Undo tablespace reached to 99.99 %

Hi all,
I am using Oracle Apex 3.1 & Database oracle 10g Release 1002000100 on HP-Unix
my Undo Tablespace is increasing Regularly, I turned off its auto Extent,
On Querying thru v$Session
user APEX_PUBLIC_USER,osuser Apache are
logged on for 16 times,
my Undo tablespace reached to 99.99 %
I now added more 500 MB,
Again it occupied to 99.99 %
I didnt temper with Undo tablespace,
usinG Default Settings except i did Auto EXTENT Turned off,
please Suggest me the Fixing & cause for this
many thanks
-Khaja
Edited by: ahuja on Feb 7, 2009 3:26 PM

Hi all
i tried with the Following
SQL> SELECT SUM(a.bytes) "UNDO_SIZE"
2 FROM v$datafile a,
3 v$tablespace b,
4 dba_tablespaces c
5 WHERE c.contents = 'UNDO'
6 AND c.status = 'ONLINE'
7 AND b.name = c.tablespace_name
8 AND a.ts# = b.ts#;
UNDO_SIZE
1.4680E+10
SQL>
SQL> SELECT MAX(undoblks/((end_time-begin_time)*3600*24))
2 "UNDO_BLOCK_PER_SEC"
3 FROM v$undostat;
UNDO_BLOCK_PER_SEC
59.7333333
SELECT d.undo_size/(1024*1024) "ACTUAL UNDO SIZE [MByte]",
SUBSTR(e.value,1,25) "UNDO RETENTION [Sec]",
ROUND((d.undo_size / (to_number(f.value) *
g.undo_block_per_sec))) "OPTIMAL UNDO RETENTION [Sec]"
FROM (
SELECT SUM(a.bytes) undo_size
FROM v$datafile a,
v$tablespace b,
dba_tablespaces c
WHERE c.contents = 'UNDO'
AND c.status = 'ONLINE'
AND b.name = c.tablespace_name
AND a.ts# = b.ts#
) d,
v$parameter e,
v$parameter f,
SELECT MAX(undoblks/((end_time-begin_time)*3600*24))
undo_block_per_sec
FROM v$undostat
) g
WHERE e.name = 'undo_retention'
AND f.name = 'db_block_size'
ACTUAL UNDO SIZE [MByte] UNDO RETENTION [Sec] NEEDED UNDO SIZE [MByte]
14000 900 420
Now my Undo tablespace reached 99% Again, i wanted to know the what is eating my Undo tablespace Space
Do I need to drop and recreate a new undo tablespace? I don't want to do this until I understand what is eating all the space. Please help me here
please Help me out
many many thanks
- Khaja
Edited by: ahuja on Feb 14, 2009 4:42 PM
Edited by: ahuja on Feb 14, 2009 4:44 PM

ORA-30036: unable to extend segment by 8 in undo tablespace 'APPS_UNDOTS1'

Hi,
A user who is trying to run a report on an EBS system, gets the following error from the application end:
java.sql.SQLException: ORA-30036: unable to extend segment by 8 in undo tablespace 'APPS_UNDOTS1'
I would have expected to see this ORA error in the Oracle database alert log as well, however this is not the case.
I increased the size of the APPS_UNDOTS1 tablespace from 1700mb with autoextend to max 3000mb, however it seems that the tablespace is not extending beyond it's original size of 1700mb. In TOAD, I see that the tablespace has not grown even after the user ran the report again. Any idea why? Is there perhaps something that needs to be adjusted on the application side as well?
Thanks.

Hi,
The tablespace is not extending and this error is not written to the alert log, but I found a trace file with the following information....
ORA-30036 happens when trying to extend undo segment SYSSMU91258636580$ (usn=9) by 8 blocks
Reason: Fail to Steal
Current undo tablespace APPS_UNDOTS1 (tsn=1)
undo tablespace current size 218240 blks, maxsize 218240 blks, fixed sized
Undo Retention (reactive): 936, Parameter Undo Retention: 900, Tuned Undo Retention: 936, High threshold Undo Retention: -2
Retention Guarantee FALSE
Does anyone know how to solve this "Fail to Steal" problem?
Btw, the query SELECT DISTINCT STATUS, SUM(BYTES), COUNT(*) FROM DBA_UNDO_EXTENTS GROUP BY STATUS; returns about 55 expired extents, therefore there are still available extents to "steal" from. So why does this fail?

0RA-30036: Unable to extend segment by 8 in Undo tablespace

Hi,
I am getting this error " 0RA-30036: Unable to extend segment by 8 in Undo tablespace ". Please Advise me how i can solve this error. Just to let u know that I don't have extra space in my Partition at OS level to increase the size of Undo tablespace. Please Advise what is the alternate option to solve this problem.
I know that I can't do coalesce on Undo tablespace any other way.
Regards

Do frecuent commits.
whats the size of your temp tablespace.
you can try reducing its size and giving to undo / rollback.
try droping unused indexes.
But man..... strart planning your space and make an annual budget for disks.

(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.

Undo tablespace increasing

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