When you process a cube that contains many partitions, you may notice lots of concurrent connections to the data source being opened.
This issue occurs regardless of the Maximum Number of Connections value in the data source properties. For example, the setting may be 10 (the default),
You may even have processing failures because of reaching the concurrent connection limit on the data source server. For example, for an Oracle database, you may receive the following error message:
OLE DB error: OLE DB or ODBC error: ORA-02391: exceeded simultaneous SESSIONS_PER_USER limit.
This issue occurs because connection pooling is not working as intended.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.