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Design and Components of AggregatesLocate this document in the navigation structure

Definition

On the Maintaining Aggregates screen in the Display of Aggregates and Their Components screen area, the aggregates and their components are displayed in a logical tree structure.

Use

This screen area is used to:

  • Define aggregates

  • Obtain information about the status of individual aggregates

You can define several aggregates for an InfoCube. However, make sure that this is useful:

  • Advantage: Aggregates improve the performance of queries

  • Disadvantage: Aggregates increase load time

    • when uploading data packages

    • during the hierarchy/attribute change run after loading master data

    • when modifying time-dependent aggregates.

To optimize an InfoCube, you should repeatedly check:

  • Whether aggregates are missing: Create new aggregates.

  • Whether existing aggregates are still being used: Delete unnecessary aggregates.

The aggregates display in the Maintenance for Aggregate screen helps you to evaluate aggregates.

Structure

Column

Information

Aggregates

Aggregates with all transferred components in a tree display

Technical Name

Technical name of the aggregate.

Save

Marks new or changed aggregates

Proposed Action

The system proposes actions, as required.

Note

Once the system has proposed a new aggregate, it recommends that you activate this aggregate. This is indicated by in this column.

Status

Created

Changed (the modified aggregate definition is no longer the same as the active aggregate definition)

Saved and active

Filled/Switched Off

Not filled with data

Filled with data

Individual components in the aggregate (see Selection Type (BW-WHM)):

By default, the system aggregates according to the values of the selected objects:

  • * All characteristic values

  • H Hierarchy level

  • F Fixed value

In the context menu of the selection type, you can change this setting.

Hierarchies

Name of the hierarchy you have selected, where applicable.

Hierarchy Level

Level of the hierarchy you have selected, where applicable.

Fixed Value

Fixed value you have selected, where applicable.

Valuation

Representation in a bar chart:

  • The greater the number of minus signs, the worse the evaluation of the aggregate: "-----" means: Aggregate can potentially be deleted.

  • The larger the number of plus signs, the better the evaluation of the aggregate: "+++++" means: Aggregate potentially very useful.

The evaluation is based on a number of criteria. The following criteria are currently used in the evaluation:

  • How does the compression of the data compare with the InfoCube: How much smaller is the aggregate compared to the InfoCube?

  • When was the aggregate last used? (See under Last Used).

Records

Number of records in the filled aggregate.

This provides information about the size of the aggregate.

Records Summarized (Mean Value)

Number of records read on average from the source to create a record in the aggregate.

Example

This example is based on an aggregate with three records. If 10 records are read for the first record in the aggregate, 15 records are read for the second record and 20 records are read for the third record, the aggregate has a mean of 15 "compressed records".

This provides information about the quality of the aggregate.

  • The greater the value, the greater the compression and better the quality of the aggregate.

    Note

    Since an aggregate should be 10 times smaller than its source, the number should be larger than 10.

  • If the value is one, the aggregate is a copy of the InfoCube. In this case, consider deleting the aggregate.

Use

Number of uses (in queries).

How often is the aggregate used for reporting?

Last Used

Date

When was the aggregate last used in reporting?

If an aggregate has not been used for a long time, deactivate or delete it.

Caution

Note that certain aggregates cannot be used at certain times (for example during vacation).

Do not delete basic aggregates that you created to speed up the change run.

Last Roll Up

Date

When was data last entered for the aggregate?

Last Roll Up By

User name of the person who scheduled roll up.

Last Changed On

Date

When was the aggregate definition last changed?

Last Changed By

User name of the person who last changed the aggregate.
Integration

Log display

When you have defined the aggregate and filled it with data, the log display is shown in the lower part of the screen.

Status overview of aggregates

There is a status display for all the aggregates in the BW system in the Administration functional area of the Data Warehousing Workbench:

In the navigation pane, under Monitors, choose Aggregates. The Status of the Aggregates screen area lists all the InfoCubes and all the existing aggregates under each InfoCube.

The structure of this screen area corresponds to the Aggregate screen area of the Maintenance for Aggregate screen. Only the status of the aggregates is displayed, not their components.

By double-clicking on for a particular aggregate, the Aggregate Display screen appears. The aggregate is displayed here together with its components.