In Oracle Exadata System Software releases earlier than 12.2.1.1.0, storage indexes can hold column information for up to eight columns. In Oracle Exadata System Software release 12.2.1.1.0, storage indexes have been enhanced to store column information for up to 24 columns.

Space to store column information for eight columns is guaranteed. For more than eight columns, space is shared between column set membership summary and column minimum/maximum summary. The type of workload determines whether set membership summary gets stored in storage index.

See Set Membership in Storage Indexes for more information.