Undo Tablespace queries

Similar Questions

• undo_segments in the undo tablespace

  (1) at least how undo_segments in undo tablespace?

  Is optimal?
  If I increase the size of the undo tablespace, undo_segments counts also have increased!

  Version of DB is 10g

  Hello

   

  The two time oracle maintains exactly 10 segments. (you can see nom_segment begins by _SYSSMU11)

  I'm not clear on what exactly 10 segments. I have undo tablespace of ~ 250 GB with 6676 stored in dba_rollback_segs.

  3) why undo tablespace with the only spaceMo 46,8125 '?

  
  

  (4) I mean why he is stiil 450Mo undo_retention even through time or same validation has occurred?

  Just Oracle - Doc

  Once a transaction is committed, the undo data are more necessary for purposes of recovery rollback or transaction. However, for consistent read purposes, long-running queries may require old undo information to produce older images of data blocks. In addition, the success of several Oracle Flashback features can also depend on the availability of the old cancellation information. For these reasons, it is desirable to keep the old information of cancellation for as long as possible.

  Introduction to the management of the automatic cancellation

  With undo tablespace, you would see extended with the status ACTIVE, EXPIRED, extents still to RUN.

  Active cancellation extended are used by transactions and will be always active, because they are needed for the restoration.

  Extensions has expired are not used by transactions, the data contained in these extended is committed and the time UNDO_RETENTION is passed, so it is not necessary for the coherence of reading and can be reused.

  Not expired extensions are extended no assets but honor UNDO_RETENTION. Transactions belonging to these bodies of cancellation are determined, but the retention time has failed, and it may be necessary for the coherence of reading!

  Paste the query result - below

  ! undo_extent_stat.SQL more

  status of collar for a30

  Select the State,

  round (sum_bytes / (1024 * 1024), 0) like MB,.

  Tour ((sum_bytes / undo_size) * 100, 0) as PERC

  Of

  (

  Select the State, sum (bytes) sum_bytes

  of dba_undo_extents

  Status group

  ),

  (

  Select sum (a.bytes) undo_size

  from dba_tablespaces c

  Join v$ tablespace b on b.name = c.tablespace_name

  Join v$ datafile on a.ts # b.ts = #.

  where c.contents = 'UNDO '.

  and c.status = 'ONLINE '.

  );

  Anand

• Problems with UNDO tablespace

  Hello
  
  DB_VERSION: 10.2.0.4
  OS_VERSION: Windows 2003 server
  
  SQL > show Cancel parameter
  
  VALUE OF TYPE NAME
  ------------------------------------ ----------- ----------------
  UNDO_MANAGEMENT string AUTO
  UNDO_RETENTION integer 900
  undo_tablespace string UNDOTBS1
  
  I know that UNDO tablespace stores the old image of o / old value when the cancellation of the user, the old value is returned to the user throgh UNDO.
  
  
  My UNDO tablespace grows up to 24GO as a developer frequently updates the database in the morning and in the evening.
  
  Basically, it runs a script to offset that includes the INSERT and UPDATE and it is important to extermely.
  
  Whenever the UNDO SCT is full, I create a new one with autoextend on, what happens if I do not autoextend?
  
  1. what would be the impact on queries, if I do like above I always created UNDO tablespace with autoextend 2Go on.
  
  2. What is the best time to drop the old UNDO tablespace?
  
  Thanks in advance.

  Dear user12000301,

  Firstly the undo tablespace is not just there to roll back the transaction. You can use the for recovery undo tablespace (roll back during the recovery of the instance), coherent reading and also for operations of blowback.

  If you have defined a tablespace undo with the goal of conservation of 15 minutes, but have fixed size then;

  http://download.Oracle.com/docs/CD/B19306_01/server.102/b14231/undo.htm

  +"+
  + The following points explain the exact impact of the undo retention UNDO_RETENTION parameter: +.

  + The UNDO_RETENTION parameter is ignored for a fixed size undo tablespace. The database can overwrite the information to cancel remaining when the tablespace space becomes low. +

  + For a tablespace undo with the option enabled AUTOEXTEND, the database tries to honor the minimum retention specified by UNDO_RETENTION period. When space is low, instead of crushing the cancellation information remaining, the self-aggrandizing tablespace' extends. If the MAXSIZE clause is specified for an auto-croissant undo tablespace when the maximum size is reached, the database can begin to replace the cancellation information remaining. +
  +"+

  Be careful with the settings to cancel it. The size, before you add the new data files in the tablespace, undo or autoextending for your pain, you must consider the DML that caused the growing undo tablespace. Necessaryly should generate redo or cancel? If so, know the total amount of undo blocks through the relevant DML.

  If you have created a with 2 GB undo tablespace and mark as CanGrow that the data file can be up to 32 GB. The DBCA you will create a petit_fichier undo tablespace but you can create another like bigfile and pretend the tablespace default undo for the operation.

  The best time to drop an undo tablespace is to wait at least undo_retention period of time has elapsed to make sure you don't need to have the copy of the coherent image transactions are committed. I think that the solution could be achieved as underlined Chinar but be careful on the active rollback segments in your database. You can also dynamically change the default undo tablespace anytime if the database uses the spfile.

  Hope that helps.

  Ogan

• It will frequently commit resolve ora-30036 (cannot extend the undo tablespace)

  I use 11.2.0.3 database. I confused on the use of validation to resolve ora-30036.

  I have the script in migration once that has many updates and I'm getting ORA-30036 (unable to extend segment by 4 in the "UNDOTBS" undo tablespace) .

  Our undo tablespace in NO mode autoextend and like this is just a one time event, we will not increase it.   He is currently 6 GB.

  We would commit determination ORA-30036 in my case? If not why? Is there a better solution to solve it.

  
  

  When I say commit frequent, I won't commit after each line, I just want to commit after may be million lines, so that my active cancellation extend turn into cancellation remaining will extend and Oracle will be able to use it in case of pressure of space.

  
  

  Note:

  UNDO_MANAGEMENT: AUTO

  UNDO_RETENTION: 2700

  Undo tablespace retention is NOGAURANTEE.

  I have the script in migration once that has many updates and I'm getting ORA-30036 (unable to extend segment by 4 in the "UNDOTBS" undo tablespace).

  Our undo tablespace in NO mode autoextend and like this is just a one time event, we will not increase it.   He is currently 6 GB.

  Why don't you increase it?

  You must use the correct size of UNDO necessary for the work that will be done.

  A lot of shops to create a for big lots new UNDO tablespace and then switch to it for batch processing. Once the task is completed, they switch back to the normal UNDO. That prevents the normal RETURN of autoextending far where it is normally necessary:

  ALTER SYSTEM SET UNDO_TABLESPACE

• Transaction is written to the log file and it is not written to undo tablespace. During a failure of the system how oracle rolls back the transaction.

  Hi all

  My question is:

  Transaction is written to the log file and it is not written to undo tablespace.

  During a failure of the system how oracle rolls back the transaction.

  I have already provided the answer, you ignored if well (you seem to only read the responses by people of your country).

  Redo log is always written * first * before * writing to the data block (redo log writing is much more aggressive). So it DOESN 'T MATTER if you lose these scriptures of rollback segment.

  Valuation: rear roller followed by roll forward, using redo log files and/or archive redo log files.

  Sybrand Bakker

  Senior Oracle DBA

• How to UNDO tablespace size?

  As legend. Thank you!

  An UNDO tablespace sizing requires three data items.

  (UR) UNDO_RETENTION in seconds
  (UPS) Number of undo the blocks of data generated per second
  (DBS) Overhead varies on position and size of the file (db_block_size)

  The necessary cancellation space is calculated as:

  UndoSpace = HEART * (UPS * DBS)

  read the Doc ID 262066.1 it has retail formula.

• Undo tablespace in oracle 10g

  Hi all;

  Hello!

  I'm confused about undo tablespace size.

  Under query showing my undo tablespace size is 120Mo.

  but DBA_TABLESPACE_USAGE_METRICS view showing the undo tablespace size is 4194302

  > > Check free space

  SQ > select t.tablespace, t.totalspace as ' TOTAL_SPACE (MB).

  round ((t.totalspace-fs.freespace), 2) as "USED_SPACE (MB)",
  FS. FreeSpace as "FREE_SPACE (MB).
  round (((t.totalspace-fs.freespace) /t.totalspace) * 100, 2) like "% used (s),"
  round ((fs.freespace/t.totalspace) * 100, 2) as "% free" of
  (select round (sum (d.bytes) /(1024 * 1024)) as totalspace,)
  tablespace dba_data_files d.tablespace_name d
  Group d.tablespace_name) t,.
  (select round (sum (f.bytes) /(1024 * 1024)) as freespace,)
  tablespace dba_free_space f.tablespace_name f
  Group of f.tablespace_name)
  FS where t.tablespace = fs.tablespace order of t.tablespace.

  
  

  TABLESPACE TOTAL_SPACE (MB) USED_SPACE (MB) FREE_SPACE (MB) % used free %

  ------------------------------ --------------- -------------- -------------- ---------- ----------

  EXAMPLE                                    100             68             32         68         32

  240 230 10 SYSAUX 95,83 4.17

  480 475 5 98.96 SYSTEM 1.04

  UNDOTBS1                                   120            120              0        100          0

  1005 75 930 USERS 7.46 92.54

  SQL > select * from dba_tablespace_usage_metrics, where nom_tablespace like '% UNDO;

  NOM_TABLESPACE USED_SPACE TABLESPACE_SIZE USED_PERCENT

  ----------------------------    ----------  ---------------  ------------

  UNDOTBS1                              440        4194302 .010490422

  This is because:

  Tablespace_size in DBA_TABLESPACE_USAGE_METRICS takes the maximum file size for CanGrow tablespace that matches maxblocks in dba_data_files.

  This is not the same value you can get from dba_data_files.

  DBA_TABLESPACE_USAGE_METRICS shows essentially the maximum size to which a data file can grow. And DBA_DATA_FILES (+ DBA_FREE_SPACE) the current size of the tablespace.

  Watch more document MOS (My Oracle Support):

  Difference in size of dba_data_files Tablespace and dba_tablespace_usage_metrics/V values $ Filespace_usage (Doc ID 455715.1)

• Concept on Undo tablespace in RAC environment

  Why we need two different Undo tablespace for two different instances in RAC environment. What are the internal mechanisms behind it? No explanation of the concept will be great for me. What will be the scenario if we have same tablespace undo for two instances?

  Thanks in advance.

  Hello

  To reduce CONTENTION and the complexity of the software.aslo oracle instances share not undo tablespace using cancel separate increase the availability of data undo files.

  Note: all instances can still read that cancel all blocks for coherent reading purposes. In addition, any instance can update the any tablespace undo during the restoration of the transaction,

  as long as undo tablespace is not currently used by another instance to cancel generation or a recovery operation.

  HTH

  Tobi

• Need information on objects not expired undo tablespace

  We are facing a problem in our database for 3-4 days.

  The objects remaining in the database increases day after day. As our ts cancel autoextend enabled, it increases the storage space.

  Currently the following is the scenario.

  SQL > SELECT DISTINCT STATUS, SUM (BYTES) / 1024/1024/1024 GB, COUNT (*)

  2 GROUP OF DBA_UNDO_EXTENTS BY THE STATE;

  STATUS GO COUNT (*)

  --------- ---------- ----------

  61.5925903 10995 REST TO RUN

  3.33197021 356 EXPIRED

  ACTIVE 18.478515625

  Thus, the remaining data 61GB while active is only 478 MB and expired is 3.3 GB.

  My questions are

  1. How can I check the object or sql query or a program that contains the data to cancel "RUN" so. How can I find the names of these objects?

  2. If I turned off autoextend undo ts if this solves the problem and take the new space to cancel from space to cancel remaining?

  Help, please.

  1. the UNEXPIRED is not bound to a query, but the UNDO for UNDO Tablespace retention period. And the Undo retention is a value set automatically when the parameter UNDO_RETENTION is minium.

  The Oracle Documentation says:

  For an undo tablespace with the AUTOEXTEND option is enabled, the database tries to honor the specified minimum retention period by UNDO_RETENTION . When space is low, instead of crushing the cancellation information remaining, the self-aggrandizing tablespace' extends. If the MAXSIZE clause is specified for an auto-croissant undo tablespace when the maximum size is reached, the database can begin to replace the cancellation information remaining.

  2. Yes this will fix the issue that now the calcution for UNDO retention is different.

• Changing data in the undo tablespace or db Oracle buffer cache

  Hello
  
  I have serious doubt in the feature of oracle architecture, when a user issues an update statement, the data blocks are transported to the db buffer cache and where the data changes are made? Made a copy data block is stored in the cache db pads and the changes are made to the block in the buffer cache? or the copy of the data block is stored in the undo tablespace and changes are made to the blocks in the undo tablespace?
  
  In singles, the changes to the data blocks are make to the db or undo tablespace buffer cache?
  
  
  Thanks in advance
  
  Kind regards
  007

  Did you have a look to the Internet for the answer?

  In short, if a trial Oracle wants to update a record in the table, it does:

  -Read the record to be changed in the buffercache
  -Audits (the record already locked, is the update allowed)
  -Put the folder (called image before) in a rollback in the UNDO tablespace segment
  -Writing redo information about this change in the UNDO tablespace
  -Lock the record
  -Write the change in registration in the buffer cache
  -Put the change also in the redo buffer
  S ' sit and wait... (for a commit or a rollback)

  When are committed:
  -Release the lock
  -Empty folder of restoration since the UNDO tablespace
  -Write a record of this change forward in the UNDO tablespace

  When rollback:
  -Release the lock
  -Rinse the record changed the buffercache
  -Read the original value
  -Empty folder of restoration since the UNDO tablespace
  -Write a record of this change forward in the UNDO tablespace

  It of here, some more specific complexity when a checkpoint occurs between the change and the commit / rollback or redo buffer has been emptied for redo files

  Please any other s/n, correct me if I'm wrong...

  See you soon
  FJFranken

• MAX limit for segment undo undo tablespace

  Hello Experts;
  
  Where tick No, max of segments of cancellation in the Oracle database?
  

  Is limited and depends on the SIZE of the DB or UNDO tablespace size?

  Thanks in advance...

  969352 wrote:
  What?

  dba_data_files - I thought that from here we can not get undo_segments County!

  not serious... Thank you...

  You started this thread, ask questions about the size of UNDO limit; which is a direct function of DBA_DATA_FILES.

  Then you changed question about County segment UNDO. which is a direct function of DBA_SEGMENTS.

  so take your decisions about what question should be answered.

• UNDO TABLESPACE MANAGEMENT

  Hello
  I'm trying to remove 90 columns of a partitioned table big. I was trying a physical decline first and since it takes more time, I decided take unused columns and drop them. However, I could put in unused condition.
  Now I'm trying to drop these unused columns in the table, it has run for 22hours approx. I'm keep increasing the undo tablespace to store the undo data.
  I have also diminished the undo_retention at 300 to 900.
  
  My question is there a better way to drop these columns. And is it possible to flush out the undo data.
  
  Your valuable response is greatly apprecaited.
  
  Thank you

  Hello

  Have you checked the link, can it help to use the checkpoint to the drop statement

  http://asktom.Oracle.com/pls/asktom/f?p=100:11:0:P11_QUESTION_ID:623063677753

• Question about Undo Tablespace?

  Hello;
  
  The necessary size of the undo tablespace is the number and size of the transactions that occur on the database. But I do not need to interview one of these transactions for a schema or table using flashback it is a way to disable transactions writing on a table or schema of undo tablespace?
  
  Published by: Ecimen on 04.Mar.2013 03:50
  
  Published by: Ecimen on 03:51 04.Mar.2013

  Ecimen wrote:

  Rob_J wrote:
  OK, it's fine, so what makes you say you build too UNDO? What is the problem you're trying to solve? Or you want to know if you could get back to CANCEL in writing?

  Our log tables generate too much to cancel because we need you connecting all these data (insert and update for the most part)... but we don't care about these log tables, we want to reduce the cancellation written for these tables logs so that we could use more flashback query timestamp older due to more space in the undo tablespace...

  I think I mentioned in my other two answers above that it is not possible to disable the generation of the cancellation, or at least I don't know that there is no way to do it! What you can do, if you are worried about the Undo tablespace grows, it is that make you a tablespace size Undo fixed by controlling the Undo data that are generated. You can use Cancel Advisor of the to do. With the Undo retention period of your proposed, she would like the size of the Undo tablespace tips and you can add about 20-30% extra size and you should be fine. But as I've already said too much, he has No way to stop generating cancellation.

  Aman...

• Full undo tablespace confusion

  Hi gurus,
  
  We have a 2 RAC on RHEL 6.2 node (11 GR 2). We have 2 undo tablespace UNDOTBS1 and UNDOTBS2. Who controls the stats of DBA_UNDO_EXTENTS it gives different results. Please help me understand the difference below the query results. Also, if possible any ORA-01555 or ORA-30036?
  
  
  
  On node 1.
  
  SQL > SELECT STATUS DISTINCT, SUM (BYTES) / 1024/1024, COUNT (*) FROM DBA_UNDO_EXTENTS where nom_tablespace = 'UNDOTBS1' group by status
  2;
  
  STATUS SUM (BYTES) / 1024/1024 COUNT (*)
  --------- -------------------- ----------
  RUN 57352.1875 6087
  64.25 5 EXPIRED
  ACTIVE 841 35
  
  1 * SELECT STATUS DISTINCT, SUM (BYTES) / 1024/1024, COUNT (*) FROM DBA_UNDO_EXTENTS where nom_tablespace = 'UNDOTBS2' group by status
  SQL > /.
  
  STATUS SUM (BYTES) / 1024/1024 COUNT (*)
  --------- -------------------- ----------
  9090,8125 1240 REST TO RUN
  ACTIVE 1374 46
  47323,75-7125 EXPIRED
  
  
  SQL > SELECT STATUS DISTINCT, SUM (BYTES) / 1024/1024, COUNT (*) OF DBA_UNDO_EXTENTS group of status;
  
  STATUS SUM (BYTES) / 1024/1024 COUNT (*)
  --------- -------------------- ----------
  REST TO RUN 66185 7322
  EXPIRED 47380 7129
  ACTIVE 2600 94
  
  
  
  On node 2.
  
  SQL > SELECT STATUS DISTINCT, SUM (BYTES) / 1024/1024, COUNT (*) FROM DBA_UNDO_EXTENTS where nom_tablespace = 'UNDOTBS1' group by status
  2;
  
  STATUS SUM (BYTES) / 1024/1024 COUNT (*)
  --------- -------------------- ----------
  57281.4375 6090 REST TO RUN
  1096 45 ASSETS
  
  SQL > SELECT STATUS DISTINCT, SUM (BYTES) / 1024/1024, COUNT (*) FROM DBA_UNDO_EXTENTS where nom_tablespace = 'UNDOTBS2' group by status
  2.
  
  STATUS SUM (BYTES) / 1024/1024 COUNT (*)
  --------- -------------------- ----------
  RUN 56404.5625 8362
  ACTIVE 1320 48
  72 2 EXPIRED
  
  SQL > SELECT STATUS DISTINCT, SUM (BYTES) / 1024/1024, COUNT (*) OF DBA_UNDO_EXTENTS group of status;
  
  STATUS SUM (BYTES) / 1024/1024 COUNT (*)
  --------- -------------------- ----------
  REST TO RUN 113575 14454
  ACTIVE 2543 93
  EXPIRED 64 1
  
  
  Why is there so much difference in the outcome. Help, please
  
  Kind regards
  Nikhil Mehta.

  Hello
  It's a bug because dependent parameters for undo retention are really time-sensitive and specific to the instance.
  It is difficult to find a perfect "global" solution. Therefore, there is no solution for this.

  Then use the bellow note to determine the correct result.

  * DBA_UNDO_EXTENTS shows incorrect results of different nodes of the PAP [1492313.1 ID] *.

  Kind regards
  Levi Pereira

• 2 undo Tablespace two ONLINE, how to remove the previous cancellation of the SCT

  Hello team,
  
  Cancel management = auto
  
  After cloning: -.
  To reclaim space, I created a different undo tablespace, both are now online, but according to oracle as soon as you go to undo tablespace, undo previous TBS gets pending offline mode, offline mode, (so this transaction ends)
  
  But in my case, UNDO the two storage spaces are online
  
  Previous TBS1 Undo :-600 GB
  
  New cancel Tb2s :-100 GB
  
  Please suggest how to remove this TBS1 online cancellation
  
  NOM_TABLESPACE ONLINE_
  ------------------------------ -------
  APPS_UNDOTS1 ONLINE
  APPS_UNDOTS1 ONLINE
  APPS_UNDOTS1 ONLINE
  APPS_UNDOTS1 ONLINE
  APPS_UNDOTS1 ONLINE
  APPS_UNDOTS1 ONLINE
  APPS_UNDOTS1 ONLINE
  APPS_UNDOTS1 ONLINE
  APPS_UNDOTS1 ONLINE
  APPS_UNDOTS2 ONLINE
  APPS_UNDOTS2 ONLINE
  
  NOM_TABLESPACE ONLINE_
  ------------------------------ -------
  APPS_UNDOTS2 ONLINE

  If I'm not mistaken not looking in the right place. In the EXPECTATION of OFFLINE status will be displayed for cancel individual segments DBA_ROLLBACK_SEGS according to.

  It will be useful.