Row chaining and Row migrate

Hi,
how to do the difference between row chaining and row migrate.
In what table may i see the difference.

http://asktom.oracle.com/pls/ask/f?p=4950:8:::::F4950_P8_DISPLAYID:4423420997870

Similar Messages

Row chaining and row migration in Oracle 10g R2/11g R2

Hi,
Due to the business rule changes, one of the numeric column in a large table (20 millions rows) will be expanded from number(8) to number(10). Also, the values of this column of each row will be updated from 6 digits to 10 digits. All the indexes that use this column will be dropped and recreated after update. I would like to know if there is any row chaining or row migration issue in Oracle 10g R2 /11g R2.
Thanks for your help

neemin wrote:
Hi,
Due to the business rule changes, one of the numeric column in a large table (20 millions rows) will be expanded from number(8) to number(10). Also, the values of this column of each row will be updated from 6 digits to 10 digits. All the indexes that use this column will be dropped and recreated after update. I would like to know if there is any row chaining or row migration issue in Oracle 10g R2 /11g R2.
Thanks for your helpIt depends.
what you do observe after TESTING against the Development DB?

Row chaining and row migration ???

hi
Can someone tell me what are the oprions to over come row chaining and row migration in 10g and 11g databases ???
thanx in advance.
s

WIP wrote:
hi
Can someone tell me what are the oprions to over come row chaining and row migration in 10g and 11g databases ???
thanx in advance.
sHi.Chained row is a row that is too large to fit into a single database data block. row migration mean is update some rows would cause it to not fit on the block anymore,then these migrates to new address.For more information see below links
http://blog.tanelpoder.com/2009/11/04/detect-chained-and-migrated-rows-in-oracle/
http://www.akadia.com/services/ora_chained_rows.html

Row migration & chaining

Hi,
we have a database which has above 600 tables(all are same schema).Everyday DML statements happen Nearly 400 tables.How to find the row migration & chaining by A SINGLE QUERY.
I would like to find everyday.Is it possible without analyze?
I know analyze command but we have to mention all the tables.

Lubiez Jean-Valentin wrote:
However, the columns CHAIN_CNT and NUM_ROWS are populated by ANALYZE statement or DBMS_STATS package.Are you sure that DBMS_STATS can be used to populate CHAIN_CNT? A default DBMS_STATS.GATHER_SCHEMA_STATS does not populate the CHAIN_CNT, for example. And I'm not aware of any way to populate that without using ANALYZE.
user3266490 - Why do you want to check this sort of thing on a daily basis? That seems exceptionally odd. Even checking it quarterly would seem like overkill. Are you actually having problems with excessive migrated rows (you can't fix chained rows, so those are basically irrelevant)? If you are, then whatever tables are having problems probably just need to be rebuilt with a more appropriate PCTFREE setting.
Justin

How row migration get eliminated by export and import the table.

Hi ,
Please let me know,how row migration get eliminated by export and import the table.
Another method,deleting migrated rows and inserting those rows from copied table,
i think the concept behind this method is,inserting these rows into new block.
pls correct me if i am wrong.
Thanks,
Kumar.

Hi!
You can also use ALTER TABLE MOVE command, or if you are on 9i you can use DBMS_REDEFINITION package.
If you have a maintainance window the easiest way would be to use alter table move.
Regards,
PP

ITL Waits and row migration.

Oracle Version 11.2.0.3 PSU3
OS: SLES11 GA 64 bit
We had an issue with ITL waits on a specific table. In test this resulted in a deadlock so as a fix we rebuilt the table with initrans 8 and pctfree 75, this has improved the situation as we no longer have deadlocks but we have had an instance of high waits for ITL slots. Our development team assure us that a maximum of 6 transactions should be active on the table in question at any given time so we should not see any waits at all. As a bonus feature the table in question is initially loaded with just the primary key columns and the rest of the data (60 columns in all) is filled in over time which can cause considerable row migration to occur has anyone else encountered an issue of this type? Does row migration use additional ITL slots? I am attempting to replicate this in a development environment but so far can not get a replication of the problem.

rp0428 wrote:
Row migration can consume excess ITL entries - every row migrated in a single transaction will allocate an ITL slot in the target block, so if you manage to get (say) 5 rows in a block migrating in a single transaction and they all migrate to the same block you will find that you have used 5 ITL slots in that block - so you can't rule out the possibility that the migration is the cause of the ITL waits.
Can you expand on that a bit and reconcile it with what you say in the ITL entry in your Oracle Scratchpad Glossary article?
http://jonathanlewis.wordpress.com/2009/06/23/glossary/
The transaction needs to acquire only one ITL entry in the block no matter how many rows in the block it changes.
If an ITL (Interested Transaction List) entry represents 'interest' by a singlel transaction why would that single transaction need more than one entry in the block when migrating rows but not when updating existing rows?
What am I overlooking?
rp0428,
There are two possible replies to that question - the absolutely straightforward one is that I forgot to mention any special cases (the "Index Explosion" bug is another, very similar, case) when I wrote that note; the "wiggle" one is that each migration event behaves like a recursive transaction, which leaves you with one ITL entry per arriving row.
Regards
Jonathan Lewis

About row-chaining, row- migration in a block

What happens during row-chaining, during inserting of a record in a block, about row-migration, update of row occurs exactly at which place in a block?

Hi,
Why Every WhereYou ask Doc Questions, better you read some oracle Doc.

ROW CHAINING 과 ROW MIGRATION

제품 : ORACLE SERVER
작성날짜 : 2002-04-10
ROW CHAINING 과 ROW MIGRATION
=============================
Purpose
Row chaining 과 Row Migration에 대해 이해하고 줄이는 방법을 확인한다.
Problem Description
Row chaining 은 단일 테이블 상의 특정 Row의 길이가 증가해서 더 이상
동일한 데이타 블럭에 들어갈수 없을때 발생한다. 이때 RDBMS는 또
다른 데이타 블럭을 찾는다. 이 데이타 블럭은 원래 블럭과 연결되어
있다. 이 경우 데이타 블럭이 하나의 I/O 작업과 동일한 양을 수행하기
위해 두 개의 I/O를 사용해야 한다는 점이다. 이 상황은 여러분의
데이터베이스 성능을 빠르게 약화시킬 것이다.
Data Block상의 하나의 Row는 길이가 증가하면서 갱신되며, Block의
Freespace가 0%일 때, Row는 Migration을 일으킨다. 물론, 전체 Row가
들어갈 만한 크기의 새로운 Block에 Row에 대한 Data가 Migration된다.
이경우 ORACLE은 Row에 대한 정보를 가져오기 위해 하나 이상의 Data
Block을 반드시 읽어야 하므로 I/O Perfmance는 감소한다.
Solution Description
1. Row chaining과 migration 확인
1) run ?/rdbms/admin/utlchain.sql
2) ANALYZE Command를 통해 Chaining과 Migrating의 횟수를 조사한다.
analyze table emp list chained rows;
2. 해결과정
1) 데이터 열을 CHAINED_ROWS 테이블의 ROWID를 사용하여 원래
테이블과 같은 행 구조를 가진 중간 테이블(intermediate table)로
이동시킨다.
2) 옮겨진 데이터 열을 CHAINED_ROWS 테이블의 ROWID를 사용하여 삭제 한다.
3) 중간 테이블로부터 열들을 다시 원래 테이블로 삽입한다.
4) 중간 테이블을 버린다.
5) CHAINED_ROWS 테이블의 레코드를 삭제한다.
이 과정이 수행되고 나면 analyze 명령은 다시 수행되야 한다. row가
다시 CHAINED_ROWS 테이블에 쌓이면 어떤 블럭에도 전체row 가 들어갈
충분한 공간이 없기 때문이다. 이것은 한 데이타 블럭의 한 row 가 너무
길어서 이거나 테이블의 PCTFREE 가 적절하지 못하기 때문이다. 전자의
경우는 chaine 현상이 일어날수 밖에 없고 후자의 경우 다음과 같이
PCTFREE 를 수정한다.
3. PCTFREE 값을 조정 하여야 하는 경우
1) 테이블에 대한 더 나은 퍼센트 프리 요소(percent free factor)를 결정한다.
2) 전체 테이블을 그 모든 의존관계(예를 들면, 인덱스, 그렌트(grants),
제약조건들 등)와 함께 export한다.
3) 원래 테이블을 버린다.
4) 새로운 사양으로 다시 만든다.
5) 테이블을 import한다.

Hi,
SQL> SELECT name, value FROM v$sysstat WHERE name = 'table fetch continued row';
NAME VALUE
table fetch continued row 163
Is this mean 163 tables contains chained rows?
Please suggest me.
Thanks
KSG

Reg: Row migration-

Hi Experts,
I got a doubt regarding the concept of 'Row Migration'.
From http://www.akadia.com/services/ora_chained_rows.html :
Migrate a row when an update to that row would cause it to not fit on the block anymore (with all of the other data that exists there currently)
But I'm getting confused is -- all the blocks will be of same size right (say 4 kb). Then migrating a row(say of 8 Kb) to another block (again of same 4 Kb), how 'll that help?
I can understand the concept of 'Row Chaining' where data is shared/divided into multiple blocks.
A nice article by Hans Forbich (but still not getting Row migration properly) -- https://forums.oracle.com/message/1806755#1806755
Am I getting the concept of 'Migration' wrongly? Please rectify me.
Help much appreciated.
Thanks,
Ranit

ranitB wrote:
Yes sure I'll do the tests, John. Thanks and much appreciated.
Could you please just clarify if my above inference is correct?
-- Ranit
Did you read your own doc reference?
Row Chaining
A row is too large to fit into a single database block
So now how does that relate to what YOU said above:
Row chaining -- occurs only when an Insert happens
Ask yourself: which of these operations (insert, update, delete) can make a row 'too large to fit into a single database block'?

ROW MIGRATION 테스트

제품 : ORACLE SERVER
작성날짜 : 2003-08-04
여기서는 row migration을 테스트 할 수 있는 방법을 알아 본다.
개요>
- migration을 테스트 할 수 있는 테이블을 만든다.
- 이전 데이타보다 훨씬 큰 데이타로 update한다.
- 테이블을 analyze하여 migration이 일어난 row들을 알아낸다.
- 임시 테이블을 만들어 상기 row를 저장한다.
- 원래의 테이블에서 migration이 일어난 row들을 삭제한다.
- 임시 테이블의 내용을 원래의 테이블에 insert 한다.
SQL> create table chain (name varchar2(100));
SQL> insert into chain values('a');
SQL> insert into chain select * from chain;
SQL> /
SQL> /
SQL> update chain set name = 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa';
256 rows updated
SQL> commit;
SQL> @?/rdbms/admin/utlchain /* chained_rows table 생성 */
SQL> analyze table chain list chained rows;
SQL> select count(*) from chained_rows; /* chained, migrated rows
확인 */
SQL> create table chained_temp as select * from chain
2 where rowid in (select head_rowid from chained_rows
3 where table_name = 'CHAIN');
SQL> delete from chain
2 where rowid in (select head_rowid from chained_rows
3 where table_name = 'CHAIN');
SQL> insert into chain select * from chain_temp;
SQL> commit;
SQL> delete from chained_rows;
SQL> commit;
SQL> analyze table chain list chained rows;
SQL> select * from chained_rows;
no row selected
Reference Documents
<Note:122020.1>

in this case the concept is row chaining: "Oracle Database stores the data for the row in a chain of one or more data blocks reserved for the segment. Row chaining most often occurs with large rows. Examples include rows that contain a column of data type LONG or LONG RAW, a VARCHAR2(4000) column in a 2 KB block, or a row with a huge number of columns. Row chaining in these cases is unavoidable." http://docs.oracle.com/cd/E11882_01/server.112/e25789/logical.htm#sthref1529

Backing up Jobs, Chains and Programs in Oracle Job Scheduler

What is the best way to back up Jobs, Chains and Programs created in the Oracle Job Scheduler via Enterprise Manager - and also the best way to get them from one database to another. I am creating quite a long chain which executes many programs in our test database and wish to back everything up along the way. I will also then need to migrate to the production database.
Thanks for any advice,
Susan

Hi Susan,
Unfortunately there are not too many options.
To backup a job you can use dbms_scheduler.copy_job. I believe EM has a button called "create like" for jobs and programs but I am not sure about chains and this can be used to create backups as well.
A more general purpose solution which should also cover chains is to do a schema-level export using expdp i.e. a dump of an entire schema.
e.g.
SQL> create directory dumpdir as '/tmp';
SQL> grant all on directory dumpdir to public;
# expdp scott/tiger DUMPFILE=scott_backup.dmp directory=dumpdir
You can then import into a SQL text file e.g.
# impdp scott/tiger DIRECTORY=dumpdir DUMPFILE=scott_backup SQLFILE=scott_backup.out
or import into another database (and even another schema) e.g.
# impdp scott/tiger DIRECTORY=dumpdir DUMPFILE=scott_backup
Hope this helps,
Ravi.

Problem with porcess chain and request

Hi experts, I need help!!
Description of the problem:
There are three ODS that load daily information through process chain to a Infocubo. The information is loaded to BW from View generated for a data base of Oracle.
Process chain for the three ODS is equal, I explain the one procedure to them:
1- It initiates the chain .
2- Blocks the View.
3- Load of data through of infoPackage.
4- If the load finishes well, then the data is delete of the View, the data is activte in the ODS and it arises to InfoCube, and if it finishes bad so unblocks the View and finishes process chain.
5- Then, reconstruct the Index.
Happens that in the three ODS when we loaded the information erase request loaded previously, then the historical one of the loads in the ODS does not stay. The three infopakages used to load the information to the ODS does not have labeled the option to erase the destiny of data, and it does not have it marked. The ODS do not have marked that option.
When I do it manually east problem does not happen. I erased process chain and I returned to create the chain porcess but it did not solve the problem.
Thank you

I just checked the documentation and found that your code is incorrect. IAlternativeName::StrValue contains value for an email address, a Domain Name System (DNS) name, a URL, a registered object identifier (OID), or a user principal name (UPN). It doesn't
contain string value for directory name (and other non-mentioned types). Instead, you need to instantiate an IX500DistinguishedName interface and initialize it from an alternative name value:
class Program {
static void Main(string[] args) {
String RequestString = "Base64-encoded request");
CX509CertificateRequestPkcs10 request = new CX509CertificateRequestPkcs10();
request.InitializeDecode(RequestString, EncodingType.XCN_CRYPT_STRING_BASE64_ANY);
Console.WriteLine("Subject: {0}", request.Subject.Name);
foreach (IX509Extension ext in request.X509Extensions) {
if (ext.ObjectId.Name == CERTENROLL_OBJECTID.XCN_OID_SUBJECT_ALT_NAME2) {
CX509ExtensionAlternativeNames extensionAlternativeNames = new CX509ExtensionAlternativeNames();
string rawData = ext.RawData[EncodingType.XCN_CRYPT_STRING_BASE64];
extensionAlternativeNames.InitializeDecode(EncodingType.XCN_CRYPT_STRING_BASE64, rawData);
foreach (CAlternativeName alternativeName in extensionAlternativeNames.AlternativeNames) {
switch (alternativeName.Type) {
case AlternativeNameType.XCN_CERT_ALT_NAME_DIRECTORY_NAME:
IX500DistinguishedName DN = new CX500DistinguishedName();
DN.Decode(alternativeName.RawData[EncodingType.XCN_CRYPT_STRING_BASE64]);
Console.WriteLine("SAN: {0}", DN.Name);
break;
default:
Console.WriteLine("SAN: {0}", alternativeName.strValue);
break;
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What is difference between Startup upgrade and startup migration.

what is difference between Startup upgrade and startup migration.

I am having the metalink note.
STARTUP MIGRATE was introduced in 9.2 as a mechanism to be sure that most everything that needs to be done to run an upgrade script or a patch script is done automatically. In the past, customers were expected to adjust certain initialization parameters prior to beginning an upgrade or applying a a patch,
but most of this is now done automatically by STARTUP MIGRATE.
When a customer starts a database in MIGRATE mode, the following ALTER SYSTEM
commands will be set automatically:
But i am not sure what exactly the meaning by startup upgrade.
and exactly the startup upgrade and startup migrate

Process Chain and CPS

Hello all,
We are currently having a problem with submitting process chains. When the chain runs it does not display any of steps in the process chain and where they are running from the job we submit (RSI_START_BW_CHAIN) So what we see is that the PC has been submited and completes in say 17seconds...however everything is still running on the system...for example our CIF PC runs for 3hrs but alls we are able to see is that the job executed from CPS with no problem. I've been digging around trying to find clear documenation about PC and CPS with little luck. Am I approaching the job submission incorrectly? We are on 7.0.3.

Hello,
You should be using the RSI_RUN_BW_CHAIN job to start process chains. Maybe you can try that first. For the rest things should be straight forward. Depending on the BW backend systems you might encounter some issues, with BW 7 the synchronization has changed and you would be better of using one of the latest 7.0.4 versions (SP6 has just been released).
Regards Gerben

Process chain and Control M

Hi Gurus
We are designing process chain for our BW solution.
We have identified the dependancies of various loads which includes flat file loads and loads from R/3.
Now we would like to control ERP and BW jobs by Control M .
I have the following questions:
1. Which portion of BW process chain do we need to plug in to Control M. ? Do we need to connect the Meta chain to control M or different process chains to Control M?
2.When we create Process chain for BW, what is the best practice? Is it good to create small chains and connect them via Meta chain? or we have to create small chains only?
3. Can we include R/3 extraction Jobs and V3 Jobs in our BW process chain? so that they will trigger when we run the process chain?
4. If we decide to run V 3 jobs after every half an hour on R3 side then how often we have to extract data to BW? and how to catch correct delta without missing single record?
I would appreciate if you can help me with your knowledge.
Thanks
Kris

Hi Kris,
Control M is a third party scheduling tool provided by BMC software.
1) You have option to either include a meta chain or individual chains in Control M .
2) It depends on how your data is extracted. If you have any dependecy jobs on sourcre system, then it is better to create small process chians and include them along with your dependecy jobs in Control M
3)you can include R/3 dependency jobs and V3 jobs in Control M. Once those jobs are finished you can run BW process chains via Control M.
4)You have several scheduling options availalbe in control M to take care of your BW and R/3 jobs.
V3 jobs collect data from R/3 application tables and fill R/3 delta queue(RSA7). when you run BW process chain it will collect all the data available from R/3 delta queue.
If both jobs are running at same time, then it is better to apply some wait time on BW jobs(in process chians).
hope this helps

Row chaining and Row migrate

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