Maintaining value mapping groups to improve system performance

by Scott Priest, Editorial Director

September 26, 2011

Data retrieval accounts for a lot of performance issues within systems. This can arise due to a number of factors -- frequent calls for data, or a large amount of memory consumption, for instance. 

SAP NetWeaver Process Integration (SAP NetWeaver PI) provides a way for you to reduce your performance issues. You can map some functions to others in an interface field, reducing the processing time.

The actual process is of course much more complicated than that, but Aaron Long of SAP Active Global Support explains it in detail in his latest SAP Professional Journal article, "Improve SAP NetWeaver PI Value Mapping Performance in a High-Volume Situation."

Before he gets into the detail of the article, which includes practical examples that show various ways this process can work, he clears up a misunderstanding about the relationship between maintaining value mapping groups and Java heap memory usage. I'll share that excerpt with you here.

The Number of Value Mapping Groups vs. Java Heap Memory Usage

You can retrieve val ue mapping groups from the cache monitoring, so it is easy to assume that the maintained value mapping groups are loaded into the memory. Therefore, you may worry about the SAP Java heap memory consumption when there is a large number of value mapping groups that you need to maintain. Does this cause an OutOfMemory error?

The answer is no, because the assumption is not fully true. The maintained value mapping groups are stored on a database table. They are not loaded into the memory until they are called by the value mapping function. Value mapping groups maintained via the Integration Directory are replicated to the runtime table XI_RUNVALMAPGR with delta cache update when they are activated. Value mapping groups maintained via the Replication Interface are directly inserted or updated on table XI_RUNVALMAPGR.

Figure 3 illustrates the heap usage before and after the 5,900,000 value mapping groups are maintained. You can see that the heap consumption does not change because of the large volume of maintained value mapping groups. They are not loaded into the memory until they are called by the value mapping function. The size is controlled by parameter

For the complete article, SAP Professional Journal subscribers can go here. For more information about SAP Professional Journal, go here.

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