When building a SAS^® OLAP cube from a star schema, the starmbrtrees file, or "star member trees" file, is created. The starmbrtrees file contains an index for each non-measure dimension in cubes that are associated with dimension tables. In essence, each starmbrtree index is a transformed version of all of the external dimension tables on a row-by-row basis, where the individual distinct level caption values are replaced by the same level ordinals that are also used in the caption files and member trees to represent those captions. Only information for those levels that are used in the cube are stored in the starmbrtrees file. Therefore, the star member trees file does not store information for columns in the dimension table that are not used by the cube.

Star member trees are intended to join fact table keys with dimension member keys when creating a MOLAP NWAY aggregation during cube loading or cube update. SAS OLAP cubes that are built using the NO_NWAY PROC OLAP option do not have use for star member trees. Star member trees should not be created for cubes that do not have a MOLAP NWAY aggregation table, which, instead, have an NWAY aggregation table defined.

However, in some cases, the starmbrtrees file is created when the NO_NWAY option has been specified. The creation of this file can increase the build time for a NO_NWAY cube, as well as cause the cube to take up more disk space with the existence of the starmbrtrees file.

Currently, there is no way to prevent the unnecessary creation of the starmbrtrees file.

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