December 23, 2013 2 minute read

SAP Screen Personas: Myth vs. Truth – Part 8: Caching

This is part of a multi-part series addressing myths about SAP Screen Personas.

In the mainstream world of IT, caching is used extensively to improve performance. Generally, caching stores information close to where it will be used. Databases have long used caching to speed performance, by keeping frequently used data close to where it will be used. Intel uses caching on its chips to keep key data closer to the CPU for faster processing. Since the early days of the Internet, Akamai replicated content in various locations so it would be closer to users. Personas uses a similar approach for processing information in tables, tabs, and grids.

We allow the screen designer to cache certain information on the client system to avoid a round trip to the server. This follows the general caching principle of putting information close to where someone will use it. So, why would you not want to cache everything to have as much information ready for instant access as possible?

There are several reasons why you would not want to do this.

Since SAP is a transactional system, storing data that changes frequently could result in your seeing stale information if your cached data no longer matches the current information.
Personas retrieves screen definitions and data from the server before it renders the screen. The more information you retrieve from the back-end, the longer it takes for Personas to render the screen. For example, if you cache all the tabs in VA01, including the tables with more than 100 columns, it will take a long time for your screen to be ready to use.

So, since we offer caching in SAP Screen Personas, how can you use it wisely?

Be very selective in which tabs you cache. Only select the ones where you need fields to build your screen. We recommend caching no more than 2-4 tabs.
Understand what is in your tabs. A few fields will render very fast. A wide table will take longer.
Hide whatever you can on the server before you send it to Personas. For example, create a table variant in SAP GUI before you design your Personas screen so you are moving less information to the client in the first place.

Caching certainly is one of the ways that Personas delivers productivity through personalization. It lets you merge information from multiple tabs onto a single screen, simplifying the screen and reducing the number of key strokes to complete a transaction. You can search on tables or use conditional formatting to highlight rows that meet specific criteria.

But, you should cache information selectively rather than caching everything.