Classic InfoSet 
A classic InfoSet provides a view of a dataset that you report on. You use the InfoSet query for this purpose. The classic InfoSet determines which tables, or fields within a table, an InfoSet query references.
A classic InfoSet can also be defined so that it can be analyzed with other BW tools.
As of Release BW 2.0B, InfoSets are used in the Business Information Warehouse for InfoObjects (master data), DataStore objects, and joins for these objects. These InfoSets are not BW Repository objects but SAP Web Application Server objects. The InfoSet query can be used to carry out tabular (flat) reporting on these InfoSets.
As of Release BW 3.0, these InfoSets are called classic InfoSets.
In addition to the InfoSet query, classic InfoSets can also be analyzed with BW tools that support BEx queries, for example, BEx Analyzer or Crystal Reports. You must specifically release an InfoSet for this purpose to use these.
More information: Releasing an InfoSet for Analysis with BW Tools
As of Release BW 3.0A, you can use transformation program RSQ_TRANSFORM_CLASSIC_INFOSETS to avoid having to fully implement classic InfoSets that were set up and used in Release BW 2.0B. This simplifies the transition. All DataStore objects and all InfoObjects, as well as their join conditions, are transferred into the new object.
Caution
The following restrictions apply:
For technical reasons, all additional definitions of the classic InfoSet (additional tables, additional fields, text fields, limits, coding for the various points in time) are not copied into the new InfoSet. Comparable definition options are not available in the new InfoSets. Alternatively, use the option available when defining BEx queries (calculated key figures, for example). For more information, see Query Design: BEx Query Designer. If this method is not a sufficient replacement for the definitions stored in a classic InfoSet, continue to use the classic InfoSet.
You cannot transform InfoSet Queries.
In the ABAP Editor (transaction SE38), start program RSQ_TRANSFORM_CLASSIC_INFOSETS. The screen appears.
On the selection screen, enter the name of a classic InfoSet in the system, as well as the name of an InfoSet that is not already in the system.
Choose
(Execute). The program checks whether transformation is possible, carries it out if necessary, and then activates the newly created InfoSet.