Best Practices for SAP BI using DB2 9 for z/OS - IBM Redbooks

and right-click to select the Simulation Update tool. Additionally, you can use
SM30 or ST05 to identify the ABAP and SQL used in expensive update and
transfer rules.
Loading data targets (ODS/InfoCube) takes too long
For this condition try to load master data before transactional data for ODS and
InfoCube. By creating all necessary SIDs and populating master data tables first,
there will be significant performance improvement because you avoid expensive
SID creation during transactional data load.
In addition, try to delete before load, if possible. Performance is gained by
deleting existing data before a complete replacement load. Deleting data from
PSA helps to reduce PSA access times. Deleting data from InfoCube helps to
reduce deletion and compression times.
You can also influence performance improvement by parallel processing. For
BW 2.x, it is not possible to have data packets/requests loaded into an ODS
object in parallel. In BW 3.x, you can load data from different requests in parallel
to an ODS activation queue. Transaction RSCUSTA2 can be used to control
data ODS data load. Here you can define a maximum number of parallel dialog
work processes, a minimum number of records per package, a server group for
load balancing, and so on.
For non-reporting ODS objects, if possible, turn off the BEx Reporting setting.
Load will be faster as Master Data SID tables do not have to be read and linked
to the ODS data. You can do this by selecting RSA1 → InfoProvider, then
double-check the ODS object and expand settings to turn off the BEx Reporting
box.
For initial large data load, there are significant database accesses to the NRIV
table to fulfill a number of range requests. You can reduce application server
access to the database by buffering the SID number range for InfoCube. This
can be done using transaction SNRO to increase the number range buffer. After
load completion, you may want to reset the number range buffer to its original
values to minimize unnecessary memory allocation. Refer to SAP note 130253
for more details.
From the RSPC graphical view of the process chain, you can drop down to the
SM37 job log to see more detailed activities. You can see whether there is index
manipulation, and which tables are being processed.
Regarding index manipulation, you need to ask whether this is necessary for
your particular loading scenario. Generally, index manipulation is effective for the
initial full load of large data because of a high volume of insertions. For the initial
load of very large data, consider dropping secondary indexes to improve loading
156 Best Practices for SAP BI using DB2 9 for z/OS