Defining the Max Item Number

Defining the Max Item Number

The entity max item number parameter has several purposes. It is an indicator of the entity’s size; it allows Board to ”know”, before data is loaded, how large an entity will be and how it compares to other entities. Board optimizes the physical data structures of entities and InfoCubes considering (among other factors) the max item number values and their ratios.

For example, if the Customer entity has a max item number value of 100,000 and the Product entity of 2,000, before loading any data, Board ”understands” that the Customer entity will be 20 times larger than the Product entity. InfoCubes having Customer and Product dimensions are therefore optimized, taking into account the fact that the Customer entity is larger than the Product entity.

When two entities are dimensions of an InfoCube, it is important that the ratio of their max item numbers reflects the same proportions as the ratio of their actual number of members. Let us consider the above example: after loading the Customer and Product entities, the number of members of the Customer entity should be greater than that of the Product entity. If, after loading data the ratio is reversed, i.e. there are more products than customers, then the system is sub-optimized; a red warning message visible in the InfoCube window highlights the sub-optimized InfoCubes.

The max item number is also a limit to the number of members that the entity can handle, therefore it must be higher than the estimated total number of entity members.

The last column of the entity window shows the entity saturation given by the percentage of entity members divided by the max. item number value.

The entity saturation must not exceed 100%. If the saturation of an entity exceeds 100% a warning message indicating the exceeding entity appears when opening the database. When the saturation of an entity exceeds 100%, you must clear the entity and redefine a higher max. item number. Note that as a consequence of clearing an entity, InfoCubes versions structured by it are also cleared.  The "In Use" column of the entities transaction indicates the presence of one or mode InfoCubes structured by that entity and currently containing data.



Let’s consider for example that you are building a database to load you company’s data and you now need to create the Customer entity. You can find out how many customers your organization has by running a query on the master files. Since a rough estimate is sufficient, you can simply ask a colleague who is likely to know the number. Let’s assume the answer is 55,000 customers. The max item number should be greater than that, to allow for growth. Consider, for example that each year there are 6,000 new customers and you need to allow for 5 years of growth, then the max item number for the Customer entity should be set to 55,000+5x6000=85,000. Always over-dimension your estimates, so in this example, to be safe, set 100,000 instead of 85,000.


Tips for choosing the max item number

It is better to largely over-dimension the max item number rather than running the risk of exceeding the entity saturation. Over-dimensioning does not affect the database’s performance levels. The only problem with excessive over-dimensioning of the max item number is the risk of exceeding the maximum number of ”cells” that can be handled in a cube. This limit is 10^24 for non-sparse InfoCube and approximately 10^30 for sparse InfoCubes. Board controls this limit by indicating any excesses in the InfoCubes configuration transaction.

Consider the following guidelines for setting the max.item number