Cluster VS pooled

hey,
what is the main difference bet cluster and pooled tables where we use which one which one is better?

Check out these threads
Difference between Cluster table & Pooled Table
Re: pooled and cluster tables
EXAMPLES
http://help.sap.com/saphelp_nw04/helpdata/en/cf/21f083446011d189700000e8322d00/content.htm
Regards,
Santosh

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Cluster and pooled tables

when we will use cluster table , pooled table and transparent tables...

FOr Tables
http://www.erpgenie.com/abap/tables.htm
For Tables
Pooled Tables, Table Pools, Cluster Tables, and Table Clusters
These types of tables are not transparent in the sense that they are not legible or manageable directly using the underlying database system tools. They are managed from within the R/3 environment from the ABAP dictionary and also at runtime when they are loaded into application memory.Pool and cluster tables are logical tables. Physically, these logical tables are arranged as records of transparent tables. The pool and cluster tables are grouped together in other tables, which are of the transparent type. The tables that group together pool tables are known as table pools, or just pools; similarly, table clusters, or just
clusters, are the tables which group cluster tables.Not all operations that can be performed over transparent tables can be executed over pool or cluster tables.
For instance, you can manage these tables using Open SQL calls from ABAP, but not Native SQL.These tables are meant to be buffered and loaded in memory, because they are commonly used for storing internal control information and other types of data with no external (business) relevance. SAP recommends that tables of pool or cluster type be used exclusively for control information such as
program parameters, documentation, and so on. Transaction and application data should be stored in transparent tables.
Table Pools
From the point of view of the underlying DBMS as from the point of view of the ABAP dictionary, a table pool is a transparent table containing a group of pooled tables which, when created, were assigned to this table pool.
Field Type Description
TABNAME CHAR(10) Table name
VARKEY CHAR(n) Maximum key length n =< 110
DATALN INT2(5) Length of the VARDATA record returned
VARDATA RAW(m) Maximum length of the data varies according to DBMS
Table Clusters
Similarly to pooled tables, cluster tables are logical tables which, when created, are assigned to a table cluster. Therefore, a table cluster, or just cluster, groups together several tables of type clusters.Several logical rows from different cluster tables are brought together in a single physical record. The records
from the cluster tables assigned to a cluster are thus stored in a single common table in the database.A cluster contains a transparent cluster key which must be located at the start of the key of all logical cluster tables to be included in the cluster. As well, a cluster contains a long field (VARDATA), which contains the
data of the cluster tables for this key. If the data does not fit into a field, continuation records are created.
Field Type Description
CLKEY1 CHAR(*) First key fields
CLKEY2 CHAR(*) Second key field
CLKEYN CHAR(*) nth key field
PAGENO INT2(5) Number of the next page
TIMESTMP CHAR(14) Time stamp
PAGELG INT2(5) Length of the VARDATA record returned
VARDATA RAW(*) Maximum length of the data section; varies according to database system
Working with Tables
The dictionary includes many functions for working with tables. There are five basic operations you can perform on tables: display, create, delete, modify, copy. Please do not confuse displaying a table with displaying the table entries (table contents). In order to display a table, it must previously exist; otherwise the system will display an error message in the status bar. For the following example, the table TABNA is used. To display this table, from the main dictionary screen, enter the table name in the Object name
input field with the radio button selected next to Tables. Then, click on the Display button at the bottom of the screen, or press the F7 function key, or, alternatively,
select Dictionary object Display from the menu.
In this screen, you can see table information such as
¨ Table type, shown next to the name of the object. In the example, it is a transparent table.
¨ Short text description.
¨ Name of the user who made the last change, and the date of the change.
¨ Master language.
¨ Table status. On the screen, you can see this table is saved and active.
¨ Development class. For information on development classes, refer to Chap. 6.
Delivery class, which sets the maintenance group for the table. It controls how tables will behave during client copy procedures, upgrades, and so forth.¨
Tab. Maint. Allowed flag, which indicates whether you can generate a screen for maintaining table entries.
¨Then, on the lower part of the screen, you can see the table fields with all associated characteristics such as:
¨ Field name.
¨ Key indicator. When set, this field is the primary key, or part of it.
¨ Data element.
¨ Basic data type.
¨ Length.
¨ Check table.
¨ Short text, describing the field.
Additional information about the table can be displayed by selecting the corresponding functions from the menu or directly from the application toolbar, such as keys, indexes, or technical settings.
Regards,
Balaji
**Rewards for helpful answers

Reg : Cluster and pool tables

Hi All,
I think this has been asked previously.
Have a doubt, i think this area is kind of opaque.
This is the scenario, we have standard business suite systems now i am going to get the data into hana using SLT how do i handle cluster and pool tables. Do i bring in the declustered data?
I am aware that we can get the data from these tables into BW on hana, not sure if that is correct.
What are the best practice approach for these table classes.
How have you implemented these kind of scenarios.
Message was edited by: Tom Flanagan

Hello,
SLT Supports replication of non-Unicode to Unicode systems.
Includes cluster / pool tables, etc. (writes into transparent tables in SAP HANA system).
Regards,
Subbu

Cluster tables , pool tables ,hashed tables?

give me the examles of cluster and pool tables & hashed tables ?

I. Transparent tables (BKPF, VBAK, VBAP, KNA1, COEP)
Allows secondary indexes (SE11->Display Table->Indexes)
Can be buffered (SE11->Display Table->technical settings) Heavily updated tables should not be buffered.

II. Pool Tables (match codes, look up tables)
Should be accessed via primary key or
Should be buffered (SE11->Display Table->technical settings)
No secondary indexes
Select * is Ok because all columns retrieved anyway
III. Cluster Tables (BSEG,BSEC)
Should be accessed via primary key - very fast retrieval otherwise very slow
No secondary indexes
Select * is Ok because all columns retrieved anyway. Performing an operation on multiple rows is more efficient than single row operations. Therefore you still want to select into an internal table. If many rows are being selected into the internal table, you might still like to retrieve specific columns to cut down on the memory required.
Statistical SQL functions (SUM, AVG, MIN, MAX, etc) not supported
Can not be buffered
IV. Buffered Tables (includes both Transparent & Pool Tables)
While buffering database tables in program memory (SELECT into internal table) is generally a good idea for performance, it is not always necessary. Some tables are already buffered in memory. These are mostly configuration tables. If a table is already buffered, then a select statement against it is very fast. To determine if a table is buffered, choose the 'technical settings' soft button from the data dictionary display of a table (SE12). Pool tables should all be buffered.
regards,
srinivas
*reward for useful answers*

Can u create cluster and pooled tables in real time

hi
can u create cluster and pooled tables in real time.can u send data base tables name of above one.

Hai Anil
For creating cluster tables first u have to create table pool ...
create a table and specify the fields and other tecnical settings and
then Goto EXTRAS --> Change Table Category and selct the Pooled table and activate it...
Then Create another table And specify the required fileds and also the settings and then
Goto EXTRAS --> Change Table Category and selct the Cluaster table and in Delivery and
Maintainence Properties mention the Pooled table that u created and activate it...
Regards
Sreeni

Doubt on cluster and pooled tables

Dear experts
i kno how to create a cluster and pooled table ..
but in reality how a requirement comes to create a cluster or pooled table....
plz kindly explain in detailed
thanks in advace
somesh

Hello,
Hope the below link gives you an insight into how the pooled/cluster tables behave.
http://help.sap.com/saphelp_46c/helpdata/EN/81/415d363640933fe10000009b38f839/frameset.htm
For better understanding on how and when to create pooled/cluster table, refer to the below examples.
All Condition tables i.e., Annn tables (pricing/discounts etc.,) belong to the table Pool KAPOL (Condition Pool) as the underlying concept is same across different condition tables, but, they have different Key (primary) fields.
Accounting Document Segment (Line Item records) BSEG is a cluster table that belongs to the table cluster RFBLG. Also, other tables such as BSEC, BSED, BSES, BSET also come under the same table cluster as all of them possess the common Key i.e., BUKRS/BELNR/GJAHR.
Please contact for further details. <removed_by_moderator>
With Regards
Vijay Gajavalli
Edited by: Julius Bussche on Sep 4, 2008 8:40 AM

Joining of cluster and pooled tables ,transparent tables

Hi,
I wanted to do join between cluster ,pooled and transparent tables but inner join won't allow to join between transparent or cluster tables or pooled tables . The requirements are that join should take place dynamically between transparent ,cluster ,pooled tables .I have written the Function module for joining multiple tables for transparent tables but unable to implement same for the transparent and cluster or pooled tables.How to handle the joining of tables between pooled or cluster and transparent tables kindly provide me the answer .
Thanks,
jahnavi.

Hi Jahnavi,
My suggestion would be... if you want to retrieve the data between cluster tables and transparent tables.. its better to go for views instead of cluster tables then that would be easier for you to retrieve the data
let us take one example BSEG its a cluster table where as there is one view VBSEGK it contains almost all the important fields needed so that u can make use of those or you can look into BSIK and BSAK tables so it better to avoid the cluster tables while retriving the data from the performance point of view

Reg cluster and pooled tables

hi experts..
can u pls give the names of some cluster and pooled tables?
regards
Sellavel

Hello,
Pooled tables can be used to store control data (e.g. screen sequences, program parameters or temporary data). Several pooled tables can be combined to form a table pool. The table pool corresponds to a physical table on the database in which all the records of the allocated pooled tables are stored.
A001
A004
A005
A006
A007
A009
A010
A012
A015
A016
A017
A018
A019
A021
A022
Cluster tables contain continuous text, for example, documentation. Several cluster tables can be combined to form a table cluster. Several logical lines of different tables are combined to form a physical record in this table type. This permits object-by-object storage or object-by-object access. In order to combine tables in clusters, at least parts of the keys must agree. Several cluster tables are stored in one corresponding table on the database.
AUAA
AUAB
AUAO
AUAS
AUAT
AUAV
AUAW
AUAY
BSEC
BSED
BSEG
BSES
BSET
CDPOS
Vasanth

Need of Cluster and Pool Table in SAP

Can anybody explain an importance of Cluster and Pool Table concept in SAP.

Hi Hema,
Given link was Helping but still I have few things as part of concept of Cluster and Pool Tables.
(1) As cluster and Pool, both are logical table in SAP, it doesn't have physical existence in Database. Means, a single database table (Actual physical in database server ) may contain more than one pool and cluster tables' data. Likewise it decrease no of Tables at database server whereas the amount of data may remain same. So, my question is how does it benefit in respect of Memory space at database server or any other means.?
(2). As per one of the difference between Cluster and Pool table - Tables pools doesn't need to have foreign key relationship whereas in case of cluster table it it must to have foreign key relationship. Why is it so..?
Hope I have brought more clarity to my doubt.
Regards,
Chetan.

Cluster and pool tables

I make a join with a pool table the compiler writes
Für Pool-Tabellen, Cluster-Tabellen und Projektions-Views ist JOIN
for pool-Tables, Cluster-Tables and Projections-View is no JOIN allowed.
What can I do to read the data from the table a005 in join.
thanks.
Waseem

>
Ahmad Waseem wrote:
> What can I do to read the data from the table a005 in join.
> thanks.
> Waseem
Hello Waseem,
Ans is DONOT use JOIN. You have to use FOR ALL ENTRIES.
You can JOIN only transperant tables. This is where JOIN scores over FOR ALL ENTRIES
BR,
Suhas

Failover cluster storage pool cannot be added

Hi.
Environment: Windows Server 2012 R2 with Update.
Storage: Dell MD3600F
I created an LUN with 5GB space and map it to both node of this cluster. It can be seen on both side on Disk Management. I installed it as GPT based disk without any partition.
The New Storage Pool wizard can be finished by selecting this disk without any error message, nor event logs.
But after that, the pool will not be visible from Pools and the LUN will be gone from Disk Management. The LUN cannot be shown again even after rescanning.
This can be repo many times.
In the same environment, many LUNs work well in Storage - Disks. It just failed while acting as a pool.
What's wrong here?
Thanks.

Hi EternalSnow,
Please refer to following article to create clustered storage pool :
http://blogs.msdn.com/b/clustering/archive/2012/06/02/10314262.aspx
Any further information please feel free to let us know .
Best Regards,
Elton Ji
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Reading Cluster and Pooled tables

Hi,
I have a requirement to read the following tables..
BSEG, KNOV, CDPOS, T6B2Fand AUAA.
out of which reading BSEG and CDPOS throwing timeout error. 20 million records each.
The idea is to read these tables and split the primary key into individual keys and dump into a Z table.
Your inputs are much valuable.
Thanks
AJ

Hi,
Please search the forum for the performance issues. These two table you've mentioned are very common giving performance issues. There are many posts on these table. Only option you have is using basic performance enhancement techniques.
Thanks.
Ravi

Normal query on cluster/pooled tables...

Hi experts,
Can i write a normal sql query on cluster or pooled tables?
Will it create any sort of problem?
Regards,
Viswanathan .S

Hi Viswanathan,
It is not recommended to access them directly due to there size like tables BSEG, CDPOS.
Report may run smooth on dev but will slow down as data increases in case of production server.
There are alternative tables available for their substitution. Which table(s) are you trying to access anyways ?
Regards,
Naveen

Where does we use Cluster & Pooled Tables

can you please tell where does we actually use the Cluster and pooled tables...and what is the main purpose of the cluster and pooled
Thankyou for your time
Bhaskar

Pooled tables can be used to store control data (e.g. screen sequences, program parameters or temporary data). Several pooled tables can be combined to form a table pool. The table pool corresponds to a physical table on the database in which all the records of the allocated pooled tables are stored.
A001
A004
A005
A006
A007
A009
A010
A012
A015
A016
A017
A018
A019
A021
A022
Cluster tables contain continuous text, for example, documentation. Several cluster tables can be combined to form a table cluster. Several logical lines of different tables are combined to form a physical record in this table type. This permits object-by-object storage or object-by-object access. In order to combine tables in clusters, at least parts of the keys must agree. Several cluster tables are stored in one corresponding table on the database.
AUAA
AUAB
AUAO
AUAS
AUAT
AUAV
AUAW
AUAY
BSEC
BSED
BSEG
BSES
BSET
CDPOS
Raja T

Cluster,pooled tables

Hi all,
What is the difference of Cluster and pooled tables.and the specific applications.do we get the need to create the pooled tables in implmentations.
u.khan.

Hai
Pooled tables. Pooled tables in the dictionary has a many-to-one relation with the table in database. Table in the database has the different name as in the dictionary. Pooled table are stored in table pool at the database level.
Several logical data records from different cluster tables can be stored together in one physical record in a table cluster.
A cluster key consists of a series of freely definable key fields and a field (Pageno) for distinguishing continuation records. A cluster also contains a long field (Vardata) that contains the contents of the data fields of the cluster tables for this key. If the data does not fit into the long field, continuation records are created. Control information on the structure of the data string is still written at the beginning of the Vardata field. A table cluster has the following structure:
Field
Data type
Meaning
CLKEY1
First key field
CLKEY2
Second key field
CLKEYn
nth key field
Pageno
INT2(5)
Number of the continuation record
Timestamp
CHAR(14)
Time stamps
Pagelg
INT2(5)
Length of the string in Vardata
Vardata
RAW (n)
Contains the entries from the data fields of the assigned cluster tables as a string, max. length n depends on the database system used
Cluster Tables
The records of all cluster tables with the same key are stored under one key in the assigned table cluster. The values of the key fields are stored in the corresponding key fields of the table cluster. The values of all data fields of the assigned cluster tables are written as a string to the Vardata field of the table cluster. Besides the actual data values, the data string contains information on the structure of the data and which table it comes from. If the string exceeds the maximum length of the Vardata field, a continuation record is written with the same key values. The continuation records for a key are distinguished by their value in field Pageno. The actual length of the string in the Vardata field is stored in the Pagelg field by the database interface.
the major difference between Standard tables, Pooled tables and Clusterd Tables?
A transparent table is a table that stores data directly. You can read these tables directly on the database from outside SAP with for instance an SQL statement.
Transparent table is a one to one relation table i.e. when you create one transparent table then exactly same table will create in data base and if is basically used to store transaction data.
A clustered and a pooled table cannot be read from outside SAP because certain data are clustered and pooled in one field.
One of the possible reasons is for instance that their content can be variable in length and build up. Database manipulations in Abap are limited as well.
But pool and cluster table is a many to one relationship table. This means many pool table store in a database table which is know as table pool.
All the pool table stored table in table pool does not need to have any foreign key relationship but in the case of cluster table it is must. And pool and cluster table is basically use to store application data.
Table pool can contain 10 to 1000 small pool table which has 10 to 100 records. But cluster table can contain very big but few (1 to 10) cluster table.
For pool and cluster table you can create secondary index and you can use select distinct, group for pool and cluster table. You can use native SQL statement for pool and cluster table.
A structure is a table without data. It is only filled by program logic at the moment it is needed starting from tables.
A view is a way of looking at the contents of tables. It only contains the combination of the tables at the basis and the way the data needs to be represented. You actually call directly upon the underlying tables.
Go through the following Link
http://help.sap.com/saphelp_nw04/helpdata/en/cf/21f083446011d189700000e8322d00/content.htm
Thanks & regards
Sreenivasulu P

Cluster VS pooled

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