Best Practices for SAP BI using DB2 9 for z/OS - IBM Redbooks
Best Practices for SAP BI using DB2 9 for z/OS - IBM Redbooks
Best Practices for SAP BI using DB2 9 for z/OS - IBM Redbooks
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7.4.4 Partitioning a DataStore object<br />
Ideally, an DataStore object would be partitioned as desired be<strong>for</strong>e it is<br />
populated with data. However, in reality it is often partitioned after it contains<br />
data (after it has become large and queries are found not to be per<strong>for</strong>ming well).<br />
Converting a <strong>DB2</strong> table from non-partitioned to partitioned involves dropping and<br />
recreating the table, so you must take care to preserve the data in the table.<br />
We recommend <strong>using</strong> a combination of <strong>SAP</strong> and <strong>DB2</strong> tools to convert an<br />
DataStore object from non-partitioned to partitioned. According to the <strong>SAP</strong> 6.40<br />
DBA Guide, <strong>DB2</strong> utilities should be used to move data between tables if the table<br />
has more than one million rows or it is larger than 100 MB. In general, DataStore<br />
object tables meet this requirement. <strong>SAP</strong> table conversion techniques use SQL<br />
SELECTs and INSERTs to per<strong>for</strong>m the data transfer, which is not as efficient as<br />
<strong>DB2</strong> unload and load utilities when processing large amounts of data.<br />
In the newer releases of <strong>SAP</strong> <strong>BI</strong>, this function will be implemented in the same<br />
way as InfoCube E- fact table repartitioning, described in 6.2, “Repartitioning of<br />
InfoCubes” on page 78.<br />
The following procedure describes how to convert an DataStore object table from<br />
non-partitioned to partitioned <strong>using</strong> table-controlled partitioning. It is taken from<br />
the <strong>SAP</strong> 6.40 DBA Guide, but it has been expanded and tailored <strong>for</strong><br />
table-controlled partitioning, as table controlled partitioning is the recommended<br />
method in <strong>DB2</strong> 9 <strong>for</strong> z/<strong>OS</strong>.<br />
1. Call transaction SE16 (Data Browser) to check the number of rows in the<br />
table to be partitioned. (This is a reality check to verify that you have the same<br />
amount of data in the table be<strong>for</strong>e and after partitioning.)<br />
2. Create a quiesce point <strong>for</strong> the entire <strong>DB2</strong> subsystem. Be sure that you have<br />
full image copies <strong>for</strong> all the <strong>SAP</strong> data. Do not allow other users write access<br />
to the <strong>DB2</strong> system until the table conversion is completed.<br />
3. Use a <strong>DB2</strong> utility to unload the data in the table to be partitioned to a<br />
sequential file. In this example, we used the <strong>DB2</strong> UNLOAD utility. See<br />
Example 7-1 <strong>for</strong> sample JCL <strong>for</strong> the <strong>DB2</strong> UNLOAD utility.<br />
Another option is to use the <strong>DB2</strong> REORG utility with the “UNLOAD<br />
EXTERNAL” option. (For complete details on the <strong>DB2</strong> utilities, refer to <strong>DB2</strong><br />
V9 Utility Guide and Reference.)<br />
Example 7-1 Example of JCL <strong>for</strong> <strong>DB2</strong> UNLOAD utility<br />
//UNLOAD JOB (999,POK),'REORG',CLASS=A,REGION=0M,<br />
// MSGCLASS=T,MSGLEVEL=(1,1),NOTIFY=&SYSUID<br />
/*JOBPARM S=SC04<br />
// JCLLIB ORDER=(<strong>DB2</strong>TU.PROCLIB)<br />
//STEP1 EXEC DSNUPROC,UID=SMPLUNLD,UTPROC=,SYSTEM=<strong>DB2</strong>T<br />
114 <strong>Best</strong> <strong>Practices</strong> <strong>for</strong> <strong>SAP</strong> <strong>BI</strong> <strong>using</strong> <strong>DB2</strong> 9 <strong>for</strong> z/<strong>OS</strong>
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