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Chapter 5. SAP usage of LOBs
This chapter discusses the usage of LOBs from the application point of view and in particular
from the perspective of SAP. This is of interest because SAP is one of the largest software
companies in the word in terms of market capitalization. It is also the largest business
application and Enterprise Resource Planning (ERP) solution software provider worldwide in
terms of revenue and an important driver of DB2 business and functionalities.
From the DB2 perspective, the SAP applications can be looked at as just one example of how
LOBs are used, or, if you prefer, misused. The points discussed in this chapter, while of
course, are in some way specific to SAP, however, can be of interest to any application or
program which uses LOBs and is running on DB2 for z/OS. Most features, ideas, or
techniques discussed in this chapter can be easily extended to other applications or
This chapter starts with a short overview of the history of LOB usages by SAP. Then, we turn
our attention to the different programming techniques used to access LOBs.
We highlight the ways in which LOB usage differs from what could be expected from a more
native DB2 point of view. There are inferences that can be drawn from the experiences and
design of the SAP applications that apply to LOB usage in a more general context.
We give some details of different optimization techniques which have been implemented into
the SAP database interface to boost the performance of LOB access. These techniques are
not particular to any application but can be used by any other persistency layer. Some of the
ideas have been implemented within the database itself in Version 9.1 of DB2 for z/OS. This
is discussed in 5.3.2, “CLI Streaming Interface” on page 136.
Traces and different possibilities to monitor LOB access are also discussed in some length.
We also briefly discuss the improvements of DB2 9 with respect to the usage of LOBs by SAP.
(c) SAP AG; 2006