Partitioning 

Use

You use partitioning to split the total dataset for an InfoCube into several, smaller, physically independent and redundancy-free units. Separating the dataset in this way improves performance when reporting and also when deleting data from the InfoCube.

Integration

Only certain database providers support this function (for example, ORACLE, INFORMIX). If you are using a database that does not support this function, this function is not provided by the BI system.

If you are using DB2/400 as the DB platform, you require database version V5R3M0 or higher and an installation of component DB2 Multi System. Note that with this system constellation the BI system with active partitioning can only be copied to other IBM iSeries with an SAVLIB/RSTLIB operation (homogeneous system copy). If you are using this database you can also partition PSA tables. You first have to activate this function using RSADMIN parameter DB4_PSA_PARTITIONING = 'X' SAP Note 815186 includes more comprehensive information on this.

Prerequisites

You can only partition a dataset using one of the two partitioning criteria ‘calendar month’ (0CALMONTH) or ‘fiscal year/period (0FISCPER). At least one of the two InfoObjects must be contained in the InfoCube.

If you want to partition an InfoCube using the fiscal year/period (0FISCPER) characteristic, you have to set the fiscal year variant characteristic to constant.

See Partitioning InfoCubes using Characteristic 0FISCPER

Features

When you activate the InfoCube, the fact table is created on the database with one of the number of partitions corresponding to the value range. You can set the value range yourself.

Choose the partitioning criterion 0CALMONTH and determine the value range

from      01.1998

to   12.2003

6 years x 12 months + 2 = 74 partitions are created (2 partitions for values that lay outside of the range, meaning < 01.1998 or >12.2003).

You can also determine how many partitions are created as a maximum on the database for the fact table of the InfoCube.

Choose the partitioning criterion 0CALMONTH and determine the value range

from        01.1998

to   12.2003

Choose 30 as the maximum number of partitions.

Resulting from the value range: 6 years x 12 calendar months + 2 marginal partitions (up to 01.1998, from 12.2003) = 74 single values.

The system groups three months together at a time in a partition (meaning that a partition corresponds to exactly one quarter); in this way, 6 years x 4 partitions/year + 2 marginal partitions = 26 partitions are created on the database.

The performance gain is only achieved for the partitioned InfoCube if the time dimension of the InfoCube is consistent. This means that with a partition using 0CALMONTH, all values of the 0CAL x characteristics of a data record have to match in the time dimension.

In the following example, only record 1 is consistent. Records 2 and 3 are not:

Note that you can only change the value range when the InfoCube does not contain data. If data has already been loaded to the InfoCube, you have to perform repartitioning.

For more information, see Repartitioning

SAP recommends “partition on demand“. This means that you should not create partitions that are too large or too small. If you choose a time period that is too small, the partitions are too large. If you choose a time period that ranges too far into the future, the number of partitions is too great. Therefore SAP recommends that you create a partition for a year, for example, and that you repartition the InfoCube after this time.

Activities

In InfoCube maintenance, choose Extras ® Partitioning and specify the value range. Where necessary, limit the maximum number of partitions.