Levels of Aggregate Storage Database Restructuring

To minimize the time and storage needed for database restructures, if a database outline changes frequently, analyze the outline and the types of outline changes.

Levels of restructuring for aggregate storage databases, listed from most to least expensive (in regard to time, storage, and data):

Table 235. Aggregate Storage Restructuring Levels

User-Outline Changes

Essbase-Restructure Level

Performance Impact

Add, delete, or move a standard dimension

Clears data and aggregate views, and performs full outline restructure

Very high

User must reload input (level 0) data, select the aggregate views, and rerun the database aggregation.

  • Add, delete, or move a hierarchy.

  • Change the number of stored levels in a hierarchy.

    See No Change in the Number of Stored Levels in a Hierarchy and Change in the Number of Stored Levels in a Hierarchy.

  • Change the top member of a stored hierarchy from label-only to stored or from stored to label-only.

  • Change a dynamic hierarchy to a stored hierarchy or a stored hierarchy to a dynamic hierarchy.

  • Change a primary or an alternate hierarchy so that it matches or no longer matches its primary or alternate hierarchy.

    All level 0 members of a primary hierarchy must be represented directly or indirectly (for example, a parent that is a sum of its children may represent its children) in all alternate hierarchies. The top level of the primary hierarchy must equate to the top level of each alternate hierarchy. For an example, see Changes in Alternate Hierarchies.

Clears aggregate views. and performs full outline restructure

Very high

Storage requirement is up to three times the size of the database file (.dat file).

User must select the aggregate views and rerun the database aggregation.

Perform a change that is not included in other categories; for example, delete or move a member, or add a member that is not the last of its siblings

Performs full outline restructure

High

Storage requirement is up to three times the size of the database file (.dat file).

Perform a light restructure change (described below) to an alternate hierarchy or an attribute dimension

Rebuilds all aggregate views that are based on attribute dimensions or alternate hierarchies

Low

Storage requirement is up to three times the size of the affected views. Such aggregate views normally exist only if you used query tracking to select views based on usage. See Selecting Views Based on Usage.

On nonattribute dimensions without stored level 0 members (for example, all level 0 members are shared or have formulas), add a child or child branch without changing the number of levels in the hierarchy.

On nonattribute dimensions with stored level 0 members:

  • Add a child as the last child of a parent without crossing a power of 2 boundary (1, 2, 4, 8, 16, and so on).

    For example, if a parent member has three children, you may add a fourth child at the end, however a fifth child will trigger a full outline restructure. For an example, see Addition of Child Members.

  • Add a child branch as the last child branch of an existing parent without crossing a power of 2 boundary and without changing the number of levels in the hierarchy.

    For an example, see Addition of Child Branches.

Examples:

  • Renames a member

  • Changes a formula

  • Changes an alias

  • Changes a dynamic hierarchy consolidation operator (for example from + to -)

Performs a light restructure; changes the outline

Very low