Transaction taking default rollback segment
Dear al,
10.2.0.4. on solaris 10
transaction taking default rollback segment
set transaction use rollback segment rbs2;
structure of rbs2:
Create rollback segment rbs2 tablespace tempt storage (initial 1M next 1M minextents 2 maxextents 1024);
alter ROLLBACK SEGMENT RBS2 STORAGE
(MINEXTENTS 20
MAXEXTENTS UNLIMITED );
set transaction use rollback segment rbs2;
when am running the query , am getting the below error :
ERROR at line 3:
ORA-01555: snapshot too old: rollback segment number 8 with name "_SYSSMU8$"
too small
why still the transaction is referring to system rollback segment "_SYSSMU8$" where I've explicitly set the rollback segment for the transactiom ?
ANy idea ?
KAI
Thanks robert and
Now, after setting
undo_retention integer
2700
It failed with the below and now it took 20 minutes..
ERROR at line 4:
ORA-01555: snapshot too old: rollback segment number 9 with name "_SYSSMU9$"
too small
ORA-02063: preceding line from TABS2CALLS
Elapsed: 00:20:11.40
Please advise
Kai
Similar Messages
-
Transaction table in rollback segments
hi guys,
I have read the following, but am still having a little difficulty conceptualising. Would someone be kind enough to give me a very brief example?
thanks
For each rollback segment, Oracle maintains a transaction table--a list of all transactions that use the associated rollback segment and the rollback entries for each change performed by these transactions.First of all, the statement is talking about old manual undo management using rollback segment.
If you check the preceding two paragraph of the statement then it's easier to understand,
It basically says, Rollback segment hold rollback entries of transaction. To make it easier to track transactions and undo entries, Oracle maintain a table to save such info.
Rollback segment , transaction and undo entries are one to many relationships.
Rollback Segment --< Transactions --< Undo Entries
http://download.oracle.com/docs/cd/B10501_01/server.920/a96524/b_deprec.htm
Contents of a Rollback Segment
Information in a rollback segment consists of several rollback entries. Among other information, a rollback entry includes block information (the file number and block ID corresponding to the data that was changed) and the data as it existed before an operation in a transaction. Oracle links rollback entries for the same transaction, so the entries can be found easily if necessary for transaction rollback.
Neither database users nor administrators can access or read rollback segments. Only Oracle can write to or read them. (They are owned by the user SYS, no matter which user creates them.)
How Rollback Entries Are Logged
Rollback entries change data blocks in the rollback segment, and Oracle records all changes to data blocks, including rollback entries, in the redo log. This second recording of the rollback information is very important for active transactions (not yet committed or rolled back) at the time of a system crash. If a system crash occurs, then Oracle automatically restores the rollback segment information, including the rollback entries for active transactions, as part of instance or media recovery. When recovery is complete, Oracle performs the actual rollbacks of transactions that had been neither committed nor rolled back at the time of the system crash.
When Rollback Information Is Required
For each rollback segment, Oracle maintains a transaction table--a list of all transactions that use the associated rollback segment and the rollback entries for each change performed by these transactions. Oracle uses the rollback entries in a rollback segment to perform a transaction rollback and to create read-consistent results for queries. -
I ported a database over to a new server.
It seems there may be transactions pending...which I don't care about.
I can log as SYS and run queries, but I cannot run DML or DDL statements.
I have narrowed down the problem to the SYSTEM rollback segment.
I am running in Automatic Undo mode.
How do I clear transactions from a rollback segment?
I don't think I can alter or create a new SYSTEM rollback segment.There is no error message.
When I issue any DML/DDL statement Oracle just hangs forever...and never issues an error message.
Here is the latest printout from the alert.log file:
Tue Jul 11 14:33:03 2006
LGWR: Primary database is in CLUSTER CONSISTENT mode
Tue Jul 11 14:33:03 2006
ARCH: Evaluating archive log 3 thread 1 sequence 14697
ARCH: Beginning to archive log 3 thread 1 sequence 14697
Creating archive destination LOG_ARCHIVE_DEST_1: 'D:\ORA92\RDBMS\ARC14697.001'
ARCH: Completed archiving log 3 thread 1 sequence 14697
Tue Jul 11 14:33:05 2006
LGWR: Primary database is in CLUSTER CONSISTENT mode
Thread 1 advanced to log sequence 14700
Thread 1 opened at log sequence 14700
Current log# 3 seq# 14700 mem# 0: D:\ORADATA\9.2\ICDB\LOG\LOG3A.ORA
Successful open of redo thread 1
Tue Jul 11 14:33:06 2006
SMON: enabling cache recovery
Tue Jul 11 14:33:06 2006
Successfully onlined Undo Tablespace 1.
Tue Jul 11 14:33:06 2006
SMON: enabling tx recovery
Tue Jul 11 14:33:06 2006
Database Characterset is WE8MSWIN1252
replication_dependency_tracking turned off (no async multimaster replication found)
Completed: alter database open
Tue Jul 11 14:33:53 2006
SMON: Parallel transaction recovery tried
Tue Jul 11 14:34:45 2006
create rollback segment system
tablespace system
storage (
initial 112K
minextents 1
maxextents 1
Tue Jul 11 14:34:45 2006
ORA-1535 signalled during: create rollback segment system
tablespace system
s...
Tue Jul 11 14:35:02 2006
Thread 1 cannot allocate new log, sequence 14701
All online logs needed archiving
Current log# 3 seq# 14700 mem# 0: D:\ORADATA\9.2\ICDB\LOG\LOG3A.ORA
Tue Jul 11 14:35:12 2006
drop rollback segment system
Tue Jul 11 14:35:12 2006
ORA-1544 signalled during: drop rollback segment system...
Tue Jul 11 14:41:33 2006
alter rollback segment system offline
Tue Jul 11 14:41:33 2006
ORA-30019 signalled during: alter rollback segment system offline... -
ROLLBACK SEGMENT의 MINEXTENTS를 20 이상으로 하면 좋은 이유
제품 : ORACLE SERVER
작성날짜 : 2003-06-19
ROLLBACK SEGMENT의 MINEXTENTS를 20 이상으로 하면 좋은 이유
=========================================================
PURPOSE
이 자료는 다음과 같은 주제에 대하여 소개하는 자료이다.
이 문서는 database application의 요구 사항을 충족시키기 위해 고려되어
져야 할 rollback segment tablespace 구성에 관한 내용을 담고 있다.
Creating, Optimizing, and Understanding Rollback Segments
-Rollback Segment 구성과 기록 방식
-Transaction에 Rollback Segment를 할당하는 Oracle 내부 메커니즘
-Rollback Segment 크기와 갯수
-Rollback Segment의 크기와 갯수 결정을 위한 테스트
-Rollback Segment extent의 크기와 갯수
-Rollback Segment의 minextents를 20 이상으로 하면 좋은 이유?
-Rollback Segment의 Optimal storage parameter와 Shrink
Explanation
Rollback Segment 구성과 기록 방식
Rollback segment는 extent라 불리는 연속적인 여러 개의 block으로 구성된다.
Rollback segment는 ordered circular 방식으로 extent를 쓰게 되는데,
current extent가 full이 되면 next extent로 옮겨 가며 사용하게 된다.
Transaction은 rollback segment 내의 current location에 record를 쓴 다음,
record의 size 만큼 current pointer를 옮겨 간다.
Rollback segment에 현재 record가 쓰여지고 있는 위치를 "Head"라고 한다.
또한, "Tail"이란 용어는 rollback segment에서 가장 오래된 active
transaction record의 시작 위치가 되는 부분을 말한다.
Transaction에 Rollback Segment를 할당하는 Oracle 내부 메커니즘
새로운 transaction이 rollback segment 를 요청하면, 각 rollback segment
를 이용하고 있는 active transaction 갯수를 확인하여 가장 적은 갯수의
active transaction 을 가진 rollback segment를 할당하게 된다.
Rollback segment는 transaction load를 처리하기에 충분한 크기를 가져야
하고, 필요한 만큼의 rollback segment를 사용할 수 있도록 적당한 갯수의
rollback segment를 가져야 한다.
1. 한 transaction은 단 하나의 rollback segment만을 사용할 수 있다.
2. 같은 extent에 여러 transaction이 기록할 수 있다.
3. Rollback segment의 Head는 Tail에 의해 현재 사용 중인 extent를
침범하지 않는다.
4. 링 형태로 구성되어 있는 rollback segment의 extent들은 다음 extent를
찾을 때 절대 건너 뛰는 일이 없으며, 순서를 뒤바꾸어 사용하지도 않는다.
5. Head가 next extent를 찾지 못하면, 새로운 extent를 추가로 할당하고,
그 extent를 링 안에 포함시킨다.
위와 같은 원리를 감안할 때, transaction size 뿐만 아니라 transaction
time도 상당히 중요한 고려 사항이라는 것을 알 수 있다.
Rollback Segment 크기와 갯수
Rollback segment size가 충분한지 판단하는 기준은 transaction activity에
직접적으로 영향을 받는다. 주로 일어나는 transaction activity에 근거하여
rollback segment size를 결정하여야 하고, 잘 일어나지 않는 특수한 경우의
큰 transaction이 문제라면 별도의 rollback segment로 관리되어야 한다.
Transaction 발생 중 Head가 너무 빨리 wrap around 시켜서 tail을 catch하
지 않도록 하여야 하며, 자주 변경되는 data에 대해 long-running query가
수행되었을 경우 read-consistency가 유지될 수 있도록 rollback segment
가 wrap around되지 않아야 한다.
Rollback segment 갯수를 적당히 잡아야 하는 이유는 process들 간에
contention을 방지하기 위함이고, V$WAITSTAT, V$ROLLSTAT, V$ROLLNAME
view를 통해서 contention을 확인할 수 있으며, 조회문은 다음과 같다.
sqlplus system/manager
select rn.name, (rs.waits/rs.gets) rbs_header_wait_ratio
from v$rollstat rs, v$rollname rn
where rs.usn = rn.usn
order by 1;
위의 query에 의해 조회된 rbs_header_wait_ratio 가 0.01 보다 크면,
rollback segment 갯수를 추가한다.
Rollback Segment의 크기와 갯수 결정을 위한 테스트
1. Rollback segment tablespace 생성
2. 테스트하기 위해 생성할 Rollback segment 갯수 결정
3. 같은 크기의 extent로 rollback segment 생성
extent 갯수는 최대 확장 시 10 - 30 개 정도가 되도록 extent 크기를 결정
4. Rollback segment의 minextents는 2이다.
5. 테스트할 rollback segment와 system rollback segment만 online 상태로 한다.
6. Transaction을 수행하고, 필요하면 application을 load한다.
7. Rollback segment contention을 확인한다.
8. Rollback segment가 최대 얼마까지 확장하는지 모니터링한다.
Rollback Segment extent의 크기와 갯수
Rollback segment가 자라나는 최대 사이즈를 알 수 있는데, 이 수치를
"minimum coverage size"라 한다. 만약, contention이 발생한다면 rollback
segment 갯수를 늘려 가면 테스트를 반복한다. 또한, extent 갯수가 10개
미만이나 30개 이상이 될 필요가 있다면 extent 크기를 늘리거나 줄이면서
테스트를 반복해 나가면 된다.
Rollback segment의 extent 크기를 정할 때, 각 extent는 모두 같은 크기로
생성할 것을 recommend한다.
Rollback tablespace의 크기는 extent size의 배수로 지정한다.
최적의 성능을 위한 rollback segment의 minextents는 20 이상이어야 한다.
Rollback Segment의 minextents를 20 이상으로 하면 좋은 이유?
Rollback segment는 dynamic하게 allocate되고, 더 이상 필요 없게 되었을 때
(만약, Optimal parameter가 셋팅되어 있으면) 모두 commit된 extent에
대해서는 optimal size 만큼만 남기고 release(deallocate)된다.
Rollback segment가 적은 수의 extent를 가질 수록, space 할당/해제 시
extent 수가 많을 때보다 큰 사이즈의 space가 할당되고, 해제된다.
다음과 같은 예를 들어 보자.
200M 정도의 rollback segment가 있는데, 100M 짜리 2개의 extent로 이루어져
있다고 가정해보자. 이 rollback segment에 추가로 space를 할당해야 할 일이
생겼을 때, 모든 rollback segment extent는 같은 크기를 가져야 한다는 점을
감안할 때, 100M 짜리 extent를 하나 더 할당해야 할 것이다.
이 결과 직전의 rollback segment 크기에 비하여 50% 만큼의 크기 증가분이
생겨나게 된 것인데, 실제 필요로 하는 space보다 더 많은 space가 할당되었을
것이다.
이와 반대로, 10M 짜리 extent 20개로 구성된 200M 짜리 rollback segment를
생각해보자.
여기에 추가로 space를 할당해야 할 일이 생겼을 때, 10M 짜리 extent 하나만
추가되면 되는 것이다.
Rollback segment가 20개 또는 그 이상의 extent로 구성되어 있다면 extent가
하나 더 증가할 경우가 생겼을 때, rollback segment의 전체 크기가 5% 이상은
늘어나지 않는다는 것이다.
즉, space의 할당과 해제 작업이 보다 유연하고 쉽게 일어날 수 있다.
요약하면, rollback segment의 extent 갯수를 20 이상으로 잡으면 space
할당과 해제가 "보다" 수월해진다.
실제로 extent 갯수를 20 이상으로 잡았을 때, 처리 속도가 훨씬 빨라진다는
사실이 많은 테스트 결과 밝혀졌다.
한가지 확실한 사실은, space를 할당하고 해제하는 작업은 cost가 적게 드는
작업이 아니라는 사실이다.
실제로 extent가 할당/해제되는 작업이 일어날 때, performance가 저하되는
일이 발생한다는 것이다.
Extent 하나에 대한 cost는 별 문제가 안 된다고 할지라도, rollback segment
는 끊임없이 space를 할당하고 해제하는 작업을 반복하기 때문에 작은 크기의
extent를 갖는 것이 cost 측면에서 훨씬 효율적이라는 결론이다.
Rollback Segment의 Optimal storage parameter와 Shrink
Optimal은 deallocate 시에 rollback segment 내에 optimal size 만큼의
extents를 유지하기 위해 사용하는 rollback segment storage parameter이다.
다음과 같은 명령으로 사용한다.
alter rollback segment r01 storage (optimal 1m);Optimal size는 storage 절 안에서 기술되어야 한다.
Optimal size 이상이 되면, 모두 commit된 extent에 대해서는 optimal size
만큼만 남기고 release된다.
즉, optimal에서 지정한 크기 만큼만 rollback segment를 유지하겠다는
뜻이며, 일정한 크기로 늘어났다가 다음번 tx이 해당 rbs를 취할 경우
optimal size만큼 resize하는 option이다.
rbs의 가장 최근에 사용된 extent가 다 차서 다른 extent를 요구할 때
이 optimal size와 rbs size를 비교하게 되며, 만약 rbs size가 더 크다면
active tx에 관여하지 않는 tail extent에 대하여 deallocation이 이루어진다.
특정 rollback segment가 너무 큰 space를 차지해서 다른 rollback segment가
extent를 발생할 수 있는 여유 공간을 부족하게 만들기 때문에 이를 극복하기
위해서 optimal size를 지정할 필요가 있다.
즉, optimal parameter를 지정하면 space availability 측면에서 효율적이다.
다음과 같이 shrink 명령을 수행하는데, size를 지정하지 않으면 optimal
size 만큼 shrink된다.
alter rollback segment [rbs_name] shrink to [size];Shrink 명령 수행 후, 바로 줄어들지 않는 경우가 있는데,
transaction이 있는 경우는 줄어들지 않고, transaction이 종료되면 줄어든다.
Optimal이 적용되는 시간은 session이 빠져 나가고 약 5~10 분 정도 걸린다.
적당한 OPTIMAL SIZE?
=> 20 ~ 30 extents 정도가 적당한데, batch job의 성격에 따라 size는 달라
지며 각 optimal의 합이 datafile의 size를 넘어도 전혀 상관없다.
Optimal size를 initial, next와 같게 주면 extent가 발생하는 매번 shrink가
일어나므로 좋지 않다.
RBS들의 평균 크기를 구하여 이것을 optimal 크기로 지정하여 사용하는 것을
권한다.
다음의 query를 이용하여 peak time에 rollback segment들의 평균 크기를 구한다.
select initial_extent + next_extent * (extents-1) "Rollback_size", extents
from dba_segments
where segment_type ='ROLLBACK';
이 크기의 평균값(bytes)을 rollback segment들의 optimal size로 사용할 수
있다.
주의할 사항은 너무 자주 shrink된다거나 optimal 값을 너무 작게 주면
ora-1555 : snapshot too old error가 발생할 확률이 높아지므로,
사용하지 않는 것이 좋을 수도 있고, 되도록 큰 값으로 셋팅해야 한다.
Rollback segment의 optimal size를 확인할 수 있는 view는 V$ROLLSTAT
이라는 dynamic view로서 OPTSIZE column에서 확인이 가능하다.
Example
none
Reference Documents
<Note:69464.1> -
Sql to find check Percent of Rollback Segment Used?
I have the following queries to find information about rollback segments.
I want the sql to find % of rollback segment used.
--rollsegs.sql
select SEGMENT_NAME, OWNER, TABLESPACE_NAME, SEGMENT_ID, status
from dba_rollback_segs order by segment_name;
select name, extents, writes, xacts, gets,waits, shrinks, aveactive, status
from v$rollname n, v$rollstat s
where n.usn = s.usn
order by name;
--rolbstat.sql
select name, rssize, hwmsize "High", optsize "Opt", wraps, extends, shrinks,
aveshrink "Aveshr", aveactive "Aveact"
from v$rollname n, v$rollstat s
where n.usn = s.usn
order by name;
set numformat 999999990;DrBurgs, there was a time when your session was assigned a rollback segment that rollback segment held all the updates performed by your session but by Oracle version 8.1 every transaction executed by your session could be assigned to a different rollback segment.
So every 100,000 or whatever value of N use choose as your commit point could result in a different rollback segment being used. You can use v$rollstat and v$transaction to monitor rollback segment usage while the job is running.
You stated that you had one rollback segment for every tablespace. There is no relation in Oracle between the number of tablespace and the number of rollback segments you should have.
You should choose the number of rollback segments to create based on the expected user load and how large a transaction you need to be able to support. For manually defined rollback segments set the initial extent size and the next extent size equal with pctincrease = 0. Then set optimal to the size you would like each rollback segment to be. This size should be large enough that shrinks do not happen often but small enough that one segment that expands will not result in other rollback segments being able to extend. By using uniform extent size you guarentee that every free extent is usable by any other rollback segment that needs to extend.
With a true warehouse you probably have very little update compared to your select load and the updates are probably load jobs. In this case you may need very few, very large rollback segments to handle the load.
HTH -- Mark D Powell -- -
ROLLBACK SEGMENT CONTENTION 점검
제품 : ORACLE SERVER
작성날짜 : 1997-01-21
ROLLBACK SEGMENT CONTENTION 점검
================================
롤백 세그먼트는 트랜잭션의 before image 를 저장하기 위해 사용되어진다.
사용되어지는 롤백 세그먼트 양은 수행되는 operation의 특성이나 변화된 데이타
블럭에 의존한다.
각 트랜젝션은 롤백 관련 데이타를 writing 하기위해 가장 먼저 롤백 세그먼트
헤더에 있는 트랜젝션 테이블을 액세스하고 트랜잭션 테이블에 slot 을 얻는다.
이것은 동시에 update 되는 데이타를 write 하기 위해 테이블에 순간적인 Latch를
필요로 한다.
If the database is update intensive and has a small number of rollback segments,
user transactions will wait on the latch to access the transaction table.
A large number of rollback segments on a query intensive database will
result in wastage of space.
The following statistics shows interesting information on the rollback
segments.
It is generated from the view v$rollstat.
Before : create table stats$begin_roll as
select rownum undo#, rssize, gets, waits, writes
from v$rollstat;
After : create table stats$end_roll as
select rownum undo#, rssize, gets, waits, writes
from v$rollstat;
select e.gets - b.gets trans_tbl_gets, e.waits - b.waits trans_tbl_waits,
e.writes - b.writes undo_bytes_written,
e.rssize segment_size_bytes
from stats$begin_roll b, stats$end_roll e
where e.undo# = b.undo#;
Included below is the statistics collected for this section:
TRANS_TBL_GETS TRANS_TBL_WAITS UNDO_BYTES_WRITTEN SEGMENT_SIZE_BYTES
270 0 0 290016
2742 0 441585 4025986
614 0 32685 1508486
591 0 37831 1508486
In the above output, the waits on transaction table are zero.
If the ratio of Trans_tbl_waits to Trans_tbl_gets is greater than 5%,
additional rollback segments should be added to the database.
In general, rollback segments should be the same size and created with
a large number of small extents.
Occasionally, large transactions may enlarge rollback segments.
The database administrator should periodically verify this and
recreate them with equal extents.I don't believe that a problem in your rollback segment can corrupt your backups, for checking if you have contention in the rollback segments you can run this query and review the results:
select class, count from v$waitstat where class like 'undo%';
These values should never be high
Hope this helps
Cynthia Pulido
Monterrey, Mexico -
Intermedia is acting crazy....
DBMS_JOB ran an overnight procedure which drops and recreates a site search index (alter rebuild ..... encounters an Intermedia 8.1.6 bug, apparently)
When I go to search the site using the site search qurey I get no hits. The DR$ tables for index are empty!
When I look at ctx_user_pending, there are 470,000 pending rows for the site search index.
SO, I start ctxsrv to process the outstanding rowsd. After an hour of this running in the background, the ctx_user_index_errors view tells me it's blown the rollback segment (snapshot too old etc..... WHY? No commits in the index update process?
Can I either:
a) 'Set Transaction..' to pick up a bigger rollback segment, or
b) Update the index another way? or
c) Have a working version of Intermedia that doesn't mark the INDEX as UNUSABLE for no apparent reason 5 minutes before your demo to your client.
Thanks
nullHello,
I tried Set Transaction to a rollback segment before creat index and it worked very well for me.
Please try a big rollback segment and use it for indexing ... it helps.
Chenthill -
Taking rollback segment and datafile offline caused application error
One of the DBA's added a large rollback segment which caused the rman backup to abort. The rollback segment was taking offline and it's datafile was taken offline, all went normally no errors. An Application started gettting errors the database and application were taking down and up, no errors on either but the problem was still there. The rbs datafile and RBS were placed back online and the application worked properly. It looks as if Oracle let us take the RBS and datafile offline with active segments in the RBS is this possible?? If so it means you can pull the rug out from under Oracle and it doesn't even complain
Pls check any transactions written in application level,
explicitly assigned to the RBs which was taken offline. -
USING DEFAULT LOCAL ROLLBACK SEGMENT
Hi,
DB Version is 10.2.0.4
Recently Noticed a MV refresh taking various time to complete. The MV refresh starts at 9pm and completes some time at 1am or 12am are sometimes very fast at 10pm. The number of records are almost same. There are no locks in the db during that time.. Opening the MV script i could see
REFRESH COMPLETE
WITH ROWID
USING DEFAULT LOCAL ROLLBACK SEGMENT
DISABLE QUERY REWRITE ASUsing default local rollback segment - is that allocation of rollback segment causes this
Referred the manul
http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/statements_6002.htm - where it says this clause is not valid if the DB is in automatic undo mode.
thanks,
baskar.lRollback segment is a concept from Oracle 8i where it last showed up. This clause is preserved only for upward compatibility, but it is obsolete.
On the other hand, why do you worry about rebuilding the complete MV? either way you perform a full refresh, not a fast refresh.
If you are concerned with the time it takes to be full-refreshed find out if it is possible to have it in fast-refresh mode, tune the underlying query and make sure there are no other concurrent processes negatively affecting the I/O throughput.
~ Madrid
http://hrivera99.blogspot.com -
Forcing a specific rollback segment on a transaction does not seem to work
Hi!
We're using Oracle 9.2.0.5.0 on Sun Solaris and we're still configured to use Rollback Segments.
We have an issue with Snapshot too old due to RBS too small on a long query I attach below for reference:
set heading off
set pagesize 0
set feedback off
set linesize 200
<<<<< SET TRANSACTION USE ROLLBACK SEGMENT UMF_RBS_LARGE_TRAN; <<<<<
SELECT ucms_cards.msisdn
|| ';;' || to_char(to_date(substr(ucms_cards.notes,14+length(ucms_cards.msisdn),19),'MM-DD-YYYY.HH24-MI-SS'),'DD/MM/YYYY HH24:MI:SS')
|| ';;' || to_char(ucms_batches.expiry_date,'dd/mm/yyyy')
|| ';;' || ucms_cards.serial_no
|| ';;' || ucms_cards.serial_no
|| ';;' || ucms_cards.batch_serial_no
|| ';;' || ' '
|| ';;' || CASE ucms_cards.card_status
WHEN 'used' THEN '1'
ELSE '0'
END
|| ';;' || CASE WHEN date_booked_in is null THEN '01/01/1970 00:00:00' ELSE to_char(date_booked_in,'DD/MM/YYYY') || ' 00:00:00' END
|| ';;' || ' '
from ucms_batches,ucms_cards, UCMS_EVENT_LOG
WHERE ucms_cards.batch_serial_no = ucms_batches.serial_no
AND ucms_cards.serial_no = substr(UCMS_EVENT_LOG.ENTITY_ID,11,length(UCMS_EVENT_LOG.ENTITY_ID)-9)
AND UCMS_EVENT_LOG.PARTY_NO in (0)
AND UCMS_EVENT_LOG.TIMESTAMP>=TO_TIMESTAMP(TO_CHAR(SYSDATE-1, 'DD-MM-YYYY') || ' 00:00:01', 'DD-MM-YYYY HH24:MI:SS')
AND UCMS_EVENT_LOG.TIMESTAMP<=TO_TIMESTAMP(TO_CHAR(SYSDATE-1, 'DD-MM-YYYY') || ' 23:59:59', 'DD-MM-YYYY HH24:MI:SS')
AND UCMS_EVENT_LOG.USER_ID LIKE 'SCP-AGENT1%'
AND UCMS_EVENT_LOG.EVENT_TYPE_ID IN (1,2)
AND UCMS_EVENT_LOG.ENTITY_TYPE_ID LIKE 'ucms_cards%'
UNION
SELECT ucms_imported_cards.msisdn
|| ';;' || to_char(to_date(substr(ucms_imported_cards.notes,14+length(ucms_imported_cards.msisdn),19),'MM-DD-YYYY.HH24-MI-SS'),'DD/MM/YYYY H24:MI:SS')
|| ';;' || to_char(ucms_imported_cards.expiry_date,'dd/mm/yyyy')
|| ';;' || ucms_imported_cards.serial_no
|| ';;' || ucms_imported_cards.serial_no
|| ';;' || DBMS_UTILITY.GET_HASH_VALUE(ucms_imported_cards.card_type,1,65536)
|| ';;' || ' '
|| ';;' || CASE ucms_imported_cards.card_status
WHEN 'used' THEN '1'
ELSE '0'
END
|| ';;' || '01/01/1970 00:00:00'
|| ';;' || ' '
from ucms_imported_cards, UCMS_EVENT_LOG
where ucms_imported_cards.serial_no = substr(UCMS_EVENT_LOG.ENTITY_ID,11,length(UCMS_EVENT_LOG.ENTITY_ID)-9)
AND UCMS_EVENT_LOG.PARTY_NO in (0)
AND UCMS_EVENT_LOG.TIMESTAMP>=TO_TIMESTAMP(TO_CHAR(SYSDATE-1, 'DD-MM-YYYY') || ' 00:00:01', 'DD-MM-YYYY HH24:MI:SS')
AND UCMS_EVENT_LOG.TIMESTAMP<=TO_TIMESTAMP(TO_CHAR(SYSDATE-1, 'DD-MM-YYYY') || ' 23:59:59', 'DD-MM-YYYY HH24:MI:SS')
AND UCMS_EVENT_LOG.USER_ID LIKE 'SCP-AGENT1%'
AND UCMS_EVENT_LOG.EVENT_TYPE_ID LIKE '2%'
AND UCMS_EVENT_LOG.ENTITY_TYPE_ID LIKE 'ucms_imported_cards%';
As you see we forced the session to use a huge RBS created for the purpose, but strangely after a long while the query fails with a RBS too small failure due to another RBS, not the one specified.
Is there any chance the UNION or any other component of the query is implicitly opening a new transaction with a different RBS associated?
Any chance to force the same RBS specified explicitly?
Thanks!
Mikealbertone wrote:
but strangely after a long while the query fails with a RBS too small failure due to another RBS, not the one specified.You misunderstand snapshot too old. It can be caused by other sessions same as by your session. Assume AFTER your session issued select some other session modified one (or more) tables ucms_batches, ucms_cards, UCMS_EVENT_LOG and committed changes. By the time your select reaches to fetch rows modified by that other session rollback extents in rollback segment used by that other session were reused. You will get snapshot too old. Bottom line - all sessions modifying table(s) used by your select must use rollback segments large enough so they are not overwritten before corresponding rows are needed by your select.
SY. -
Is "SET TRANSACTION USE ROLLBACK SEGMENT" only a hint
I have two users, one makes some inserts in a table.
The other makes a select which visits many rows.
I have a big rollback-segment.
To ensure, both users use this rollback-segment I created a logon-trigger:
CREATE OR REPLACE TRIGGER a_logon AFTER LOGON
ON DATABASE
WHEN ( USER IN ( 'SCOTT', 'BOB' ) )
BEGIN
SET TRANSACTION USE ROLLBACK SEGMENT rbs_big;
END;
But I still get "snapshot to old" messages from the select, which contains the name off an other rollback-segment in the message.
The trigger really fires, i tested it by adding an insert-statement to a log-table.
What`s wrong ?The set transaction use rollback segment lasts only until you commit or rollback first time and all other transactions in that session will not be forced to that rbs anymore. Other possible solution could be that other users are accessing same tables / updating them so those sessions can't keep the read consistent image available anymore for your sessions.
-
Does a single transaction, spreeds accross multiple rollback segments?
Hi,
Does a single transaction, spreeds accross multiple rollback segments?
What if , there is not enough space in the allocated rollback segment?
Thanks
Naveen.With the additional note/ caveat that, assuming you're using a moderately recent version of Oracle and using automatic UNDO management, which you really, really ought to be doing, Oracle is constantly adding, removing, and expanding the rollback segments, making it all but impossible for a rollback segment to be too small unless it (along with all the other active redo segments) exceed the size of your UNDO tablespace.
Justin -
Rollback segment for set transaction
there is way that i can setup a rollback segment for a spacific user or specific transction.
ALTER ROLLBACK SEGMENT big_rbs ONLINE;
SET TRANSACTION USE ROLLBACK SEGMENT big_rbs;
sql .....
commit;
ALTER ROLLBACK SEGMENT big_rbs OFFLINE;
the sql is going for about hour, i was woundering during that time can some else use this rollback segment. i just want this rbs to this user, how i can do that.
thanksI guess i didn't clearify well. let say i created a rbs for specific tranction. before this transaction is start it will turn on this rbs and once this transaction is completed, it issue the command commit, and bring it back to this rbs offline. the question is durning this transaction does any other transaction can come and use this rbs instead of we have lot of other rbs.
I hope that you get my point. -
TRANSACTION을 ROLLBACK SEGMENT에 할당하는 방법(SET TRANSACTION USE)
제품 : ORACLE SERVER
작성날짜 : 2003-04-04
TRANSACTION을 ROLLBACK SEGMENT에 할당하는 방법
==============================================
(SET TRANSACTION USE ROLLBACK SEGMENT)
Purpose
Batch job 등을 사용할 때 특별히 크게 만든 rollback segment를 사용하도록
할 수가 있다. transaction에 특정한 rbs를 지정하는 방법을 알아보자.
Explanation
Oracle은 다음과 같은 규칙에 의해 각 Transaction이 사용하는 Rollback
segment를 결정한다.
1. Active Transaction의 수가 가장 작은 Rollback Segment에 할당한다.
2. 만약 1의 조건에 만족하는 Rollback segment가 하나 이상이면, 가장
마지막에 할당된 rbs 다음의 rbs를 할당한다. 이것은 undo 기능을 더
오래 지속시키도록 해 준다.
그러나, Application이 큰 rollback segment가 필요하다면 위와 같이
자동적인 rollback segment의 할당이 아닌 Manual하게 특정 rollback
segment를 할당 가능하다.
다음의 방법을 사용한다.
1) 큰 rollback segment를 만든다. 큰 rollback segment 를 만들기
위해서는 rbs tablespace에 영역이 충분히 커야 하므로 필요할 경우
tablespace를 확장하는 작업을 한다.
<tablespace 확장>
$ sqlplus system/manager
sql> alter tablespace rbs add datafile '?/rbs1SID.dbf' size 100m;
<rollback segment 생성>
sql> create rollback segment big_rbs storage(initial 10m next 10m)
tablespace rbs;
sql> alter rollback segment big_rbs online;
2) Transaction 를 assign 한다.
<sqlplus>
SQL> set transaction use rollback segment big_rbs;
<pro*c>
exec sql commit work;
exec sql set transaction use rollback segment big_rbs;
<forms>
dbms_transaction.use_rollback_segment('big_rbs');
이와 같이 지정하면 이후에 commit 또는 rollback이 일어날 때까지
한 transaction에만 해당된다. -
Cleanup log running transactions ..rollback segments
Is there any metric in OEM which does the following...
Am trying to read the document and find the metric which does the following ..not having much luck...
#* Description : Process to monitor and notify DBA about any in-doubt
#* transaction which is holding ROLLBACK Segment and
#* troubling system resources for longer time.
Thank youBelow are more details on what it does...trying to find if any metric in OEM does this...thank you
$sql_text = "select c.USN ";
$sql_text .= ",d.name ";
$sql_text .= ",c.EXTENTS , ";
$sql_text .= "a.username , a.osuser , a.sid , a.process, a.status ";
$sql_text .= ",b.start_time ";
$sql_text .= ",b.status trans_stat, b.used_ublk*value as Bytes_Used ";
$sql_text .= ",b.used_urec as Records_used ";
$sql_text .= ",start_uext as First_Extent ";
$sql_text .= ",a.MACHINE ";
$sql_text .= ",a.TERMINAL ";
$sql_text .= ",a.PROGRAM ";
$sql_text .= "from v\$session a, ";
$sql_text .= " v\$transaction b, ";
$sql_text .= " v\$rollname d, ";
$sql_text .= " (select value from v\$parameter ";
$sql_text .= " where name = 'db_block_size' ) e , ";
$sql_text .= " v\$rollstat c , ";
$sql_text .= " dba_rollback_segs f ";
$sql_text .= "where b.ses_addr = a.saddr (+) ";
$sql_text .= " and c.usn = b.xidusn (+) ";
$sql_text .= " and d.usn = c.usn ";
$sql_text .= " and f.segment_id = c.usn ";
$sql_text .= " and a.status = 'INACTIVE' ";
$sql_text .= " and b.used_urec <=${rec_used} ";
$sql_text .= " and (round((sysdate - to_date(start_time,'mm/dd/yy HH24:mi:ss'))*1440)) >= ${time_interval} ";
$sql_text .= " and a.username <> 'DMIRROR'
Maybe you are looking for
-
EPMA Windows Services not starting
Before you all jump on me, I've read almost all of the threads and documentation concerning this issue that are out there. I've checked the databases and they are configured appropriately, I've checked the IPv6 settings and they are ok. this EPMA ins
-
Final Cut Pro version 5.0.4
Hello Everyone: I have a question for you: Do you know if I can use Final Cut Pro version 5.0.4 to capture the files (video) that was shot with the new Sony HVR-Z7E video camera. Thanks Damon
-
How can i get out of a bootloop and reinstall os x without disk
now here's the kicker. I cant seem to get. out of boot loop on imac I just recently bought off of craigs list, When i can by holding d It brings up os x installer. Then prompts Can not install os x on this mac or something like that. I tried bootab
-
VAT Return(Tamilnadu Format) using XL Reporter
Hi Guru's, I need Monthly VAT Return(*.rcr) Report I have a VAT Return report for delhi state,But its too different when compare to Tamilnadu format.So,anyone completed these Report plz send it to me. Otherwise guide me how to make ch
-
How to know when a session has gone by closing browser or leaving site.
Hi! I'm doing an application that uses the session API. This application must run in every java-enabled web-server. I want to know if there is a way to know when a session has gone. I mean, you can know this if, for example, you call the isNew method