i'm facing a problem while i'm inserting millions of record from table to table that undo tablespace reach 100% full and execution aborted. , how can free the undo tablespace ??? many of extendes are offline. will it flush automatically ??? or what i should do
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regarding sizing undo tablespace and undo_retention parameter.we have to implement the database in production system with 40 users but how much space should be allocated to undo tablespace is there any propotions related to virtual memory and the
parameter.i have gone thru oracle doc's and some related sites.its an ERP aplications that contains 20 modules .I am an new one to this dba level
I created manually a database in 10g, after succesfully creating the dB, I created a single user re: LAMS. Now, I noticed that my USERS tablespace is currently at a 99.96% usage:
SQL> @check_space_used.sql
Monday, March 14, 2011 2:46:22 PM SGT
TABLESPACE_NAME TOTALSPACE TOTALBYTES PERCENTUSED
------------------------------ -------------------- -------------------- --------------------
SYSTEM 1073741824 239599616 23
UNDO 268435456 16449536 7
[code]...
I have created an user named "Raja" with a default tablespace as "Raja_TBS" along with a datafile "rajadata.dbf". I have taken the tablespace offline
SQL> alter tablespace raja_tbs offline;
Tablespace Altered. when I take a tablespace offline, which means I cannot read or write and the tablespace is currently unavailable for users. I am still able to create a table on the "Raja_TBS" while it is offline.
As the undo segments are used in round robin fashion, Is it possible that with varying load (concurrent users, size and number of transactions), the size of Undo tablespace on a particular day is less than the Undo tablespace size few days back, by any chance?
As a basic understanding I know that Undo is preserved for read consistency and transaction, instance recovery So if there are lot of transaction on a database on 05 Feb and before that, but there aren't any transactions on 6,7,8,9, then on 10th Feb can we see the Undo tablespace size is less than that of 05 Feb?
In the following case when data belonging to table is not required for any queries, transactions, even then the undo size is not restored upon dropping the table.
As such for large operations and batch processes shall we keep undo tablespace with files as 'Autoextend' with 'Maxsize' as 'Unlimited'?
SQL> select b.tablespace_name, Total_Kbytes_Available/1024 Tot_Mbytes_Available,
Kbytes_alloc/1024 Mbytes_allocated, kbytes_free/1024 Mbytes_Free_from_allocated,
((Kbytes_alloc - kbytes_free)*100/ Total_Kbytes_Available) Pctused
2 from ( select sum(bytes)/1024 Kbytes_free,
3 tablespace_name
4 from sys.dba_free_space
[code]....
we have a situation where both undo tablespaces were almost filled i.e UNDOTBS1 99% and UNDOTBS2 100% filled so i add data files to it and then i found a lot of blocking session and was just killing them through EM then i stop my front end listener and also down the service, now i don't have any blocking session but on EM a big WAIT is coming. alert log shows nothing serious, it was showing deadlock but now it is over as well.
View 8 Replies View Relatedyou have an undo tablespace which has autoextend on feature.after a timegap your undo tablespace presently is 100GB
here as a DBA what you will do?
Tablespace usage alerts are checked every ten minutes. You can request a check every minute when you set the threshold, and confirm that this has been set:
orclz> execute DBMS_SERVER_ALERT.SET_THRESHOLD(-
> metrics_id => DBMS_SERVER_ALERT.TABLESPACE_PCT_FULL,-
> warning_operator => DBMS_SERVER_ALERT.OPERATOR_GT,-
> warning_value => '50',-
> critical_operator => DBMS_SERVER_ALERT.OPERATOR_GT,-
> critical_value => '75',-
[code]....
orclz>but you will still have to wait up to ten minutes for the alert to be raised. know whether this frequency can be changed? And why this particular alert behaves differently from all the others? This is the bahaviour in all releases since server alerts arrived.
When I am importing, I get these errors
IMP-00019: row rejected due to ORACLE error 1
IMP-00003: ORACLE error 1 encountered
ORA-00001: unique constraint (XXXXXXXXXXXXXXXX) violated
Column 1 2
Column 2 OFFLINE
[code]....
I added a datafile in undo tablespace (its an ASM database). I doubt that since I added the datafile to undo tablespace, I am getting this error.
If the temp space left is 0%, i.e. all temp space used up, is it possible to make new DB connection ( can new users still connect to the DB)?
Or re-phrasing the question... How much of temp space (if at all ) is required for a new user to login to DB? Like SORT_AREA_SIZE in PGA. So, as memory sort area is already used ( Temp space is 100% full), can DB make more new connections?
I have a partitioned table - 128 partitions.
If I am not using data of many partitions in any way, will it affect my performance if I am firing select query that uses other/active partitions data.
How can I check when that partitioned was last accessed, also can I brought those inactive partitions offlie? If we can, what will be the advantages or disadvantages of that?
In an attempt to take older data off line and allow database refreshes to be faster, tablespaces associated with partitioned table data for a given time period was taken off line, leaving only tablespaces that relate to the current time period online. In effect, tablespaces related to 2010 and earlier were taken offline from a table.
1. Without giving a filter on the partition key (the business date) to scan for data greater than the dates in the off lined tablespace partition, we get a ORA-376/ORA-1110 error (data file cannot be read at this time).
2. Materialized views using fast refresh or refresh on commit, will also not work because of the partitions being off line.
Queries directly querying the tables are manageable from an application point of view.But the materialized views failing to aggregate is a bigger problem.
how we can manage this situation? I know that I can move the partitions to a different table in a tablespace to be taken off line. But if possible, we wanted to solve this without doing a move partition.
I want to drop a datafile in my test db which is in no archive mode,at first, i want to offline the datafile,but it failed,is there any way to do it?
SQL> archive log list;
Database log mode No Archive Mode
Automatic archival Disabled
Archive destination USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence 3237
[code].......
when i make a datafile offline,can i add the following option: normal or immediate?
such as like here:
SQL> ALTER DATABASE DATAFILE 5 OFFLINE NORMAL;
OR
SQL> ALTER DATABASE DATAFILE 5 ONLINE IMMEDIATE;
when i try a test ,it occurs an error:ORA-00933.
I started database in mount state;startup mount; alter tablespace users offline;
I tried to make tablespace offline In another case online but showing error database not open same for command alter tablespace begin backup; do think we can make tablespace offline in mount...
I have a long running transaction (more than 3 hours), and at the same time other operations are occurring on different tables, using the same UNDO space.
Sometimes we see ORA-30036, but this error occurs very late in the process. The transaction normally takes 3 hours, but when UNDO space is full, we do not get ORA-30036 upto 8 hours or 9 hours of process.
I am wondering what could be happening in the background, when UNDO space is full, which makes the transaction to extend upto 8 hours or 9 hours (pl. note, this transaction gets completed within 3 hours normally). This is in 11g, UNDO space is managed manually.
what is the role of undo cache or undo tablespace in recovery?
View 3 Replies View RelatedI have a question ragarding undo tablespace. I want to ask that why only undo tablespace information we need to specify in parameter file. We do not specify any other tablespace information. Not even for temporary tablespace. Then why we need to give undo tablespace name while instance is creating.
View 5 Replies View RelatedIf we insert a row in a database table then the new row stays at database buffer cache in SGA (until commit), right?. The target table is not affected (before commit). The new row is saved after commit.
I saw a concepts at Sybex oracle 10g oca book (Page 406) as follows:
" INSERT statements use little space in an undo segment; only the pointer to the new row is stored in the undo tablespace. To undo an INSERT statement, the pointer locates the new row and deletes it from the table if the transaction is rolled back. "
My question is If the row is not saved at table before commit, if we issue rollback then how oracle delete from table? I think the new row is deleted from database buffer cache in SGA.
I have been reading various articles about the undo management. This basic concept of undo management is simple but how oracle implements it is bit harder for me to grasp.
What i have read and understood is that whenever a DML(Update, Delete, Insert) statement is issued by a user, the data is fetched from datafile to database buffer cache and at the same time a copy of the original data is saved in undo segment. Now if other users requests the same data, they are presented with the unchanged copy in the undo segment.
Now I have the following questions:
1) In case of Insert statement, what data is saved in undo segment. Is it the complete data in the table to which we want to insert the new row?
2)When the user issues DML statement, there are three copies of the same data, one in Memory (which is changed and not the same as original data), second in Undo segment (Which is unchanged copy of original data) and third in datafile file ( which is original data). What is the difference in the data in undo segment and data in datafile at this stage. Why are the other users presented with the data from undo segment rather than original data from the datafile to maintain read consistency.
3)When the user issues rollback, the changes made to the copy of data in memory are undone.The copies of data in memory and undo segment are now same?. What happens to the before change copy in undo segment. Is it still there or deleted.
i have a tablespace which contains 121 datafile(max limit reached) as a dba what we have to do?
creating a new tablespace with a datafile and assign the users to the current tablespace which i created now.iif the above process is correct,after some time the tablespace which was filled up got freed up.now can i give the access to the users previous (i.e. freed up tablespace) and current tablespaces
My database version is
Oracle Database 11g Enterprise Edition Release 11.1.0.7.0 - 64bit Production
PL/SQL Release 11.1.0.7.0 - Production
CORE 11.1.0.7.0 Production
TNS for Linux: Version 11.1.0.7.0 - Production
NLSRTL Version 11.1.0.7.0 - Production
My os version is
Linux damdat01 2.6.18-128.7.1.el5 #1 SMP Wed
Aug 19 04:00:49 EDT 2009 x86_64 x86_64 x86_64
GNU/Linux
My database is OLP system.
My question is what are the advantages and disadvantages having one single tablespace versus multiple tablespace?
Easy to maintain when you have single tablespace. but hard to track the IO issues if you have one single tablespace.
understanding a redo/undo concept . Refer following data
create table t(n number);
insert into t values(10);
commit;
now I update as following
update t set n=20;
As per my understanding the before image i.e. n=10 is stored in undo (to be used for rollback, transaction recovery and even in instance recover but not in media recovery) and after image n=20 is stored in redo (to be used for various recovery purposes including media recovery in case of consistent backup).
So it is redo logs for rolling forward and undo for rolling back making transaction, db consistent . If my above understanding is true then what is meant by the term 'redo required for undo'?
Also, if there are 2 database db1 and db2 connected using database link where we are populating t1 table in db1 using t2 table in db2 using db link where redo and undo will be updated db1 or db2?
At a time my 20 GB undo tablespace was full. So i increased the tablespace size upto 48 GB. Then i saw 45 GB was used. Then i changed undo_retention=60. After that am seeing that 48 GB is full.
1) why it's happened?
2) Here what is the effect of undo_retention=60
3) How to resolve?.
Can an undo tablespace be too large and actually hurt performance? I have seen a system with a dedicated 1 TB drive for undo tablespace (no guarantee) with an undo_retention of 7 days. Would this hurt performance? What about setting an undo_retention of 24 hours with no guarantee? The only mention I could find online said that it would not hurt performance but I wanted to double check. You would think that Oracle does not care if it deletes the undo at 15 minutes or if it deletes the undo at a later date such as 7 days later and the performance should stay the same.
View 3 Replies View RelatedI am trying to drop 90 columns from a big partitioned table. I was trying a physical drop first and since it is taking longer time I decided make the columns unused state and drop them. However I was able to set them to unused state.
Now I am trying to drop those unused columns from the table, it is running since 22hours Apporox. I am keep increasing the undo tablespace to retain the undo data.
I also have decreased the undo_retention to 300 from 900.
My question is there any better way to drop these columns. And is there any way to flush out the data from undo.
S:Solaris
DB:10g
I am simulating a recovery of drop undo tablespace. for the same I have done the following things:
1. Dropped the only undo datafile from the os level while the database was open.
2. Then I created a table and inserted and updated some values in it and I was also allowed to commit.
When I am updating the rows of the table,the before images must have been written to UNDO but in my case there is no UNDO datafile.
i Cannot drop old undo tablespace. While dropping the old undo tablespace we get an error
ERROR at line 1: ORA-01548: active rollback segment '_SYSSMU77$' found, terminate dropping tablespace
SQL> select tablespace_name, status, segment_name from dba_rollback_segs where status != 'OFFLINE';
TABLESPACE_NAME STATUS SEGMENT_NAME
------------------------------ ---------------- ------------------------------
SYSTEM ONLINE SYSTEM
APPS_UNDO NEEDS RECOVERY _SYSSMU77$
When i takeind export i got error like this..
ORA-39125: Worker unexpected fatal error in KUPW$WORKER.GET_TABLE_DATA_OBJECTS while calling DBMS_METADATA.FETCH_XML_CLOB [TABLE_DATA:"POS"."TBK_POS_FACT":"KROATL200404"]
ORA-01555: snapshot too old: rollback segment number 1 with name "_SYSSMU1$" too small"
from this can we increase the undo_retention value or undo tablespace size?
I'm an Oracle novice and from what I've read so far, it seems that you should be able to do rollbacks and data recovery using the redo logs. I'm having a difficulty understanding the need for the undo tablespace.
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