SQL4009 - Index created for table &1

SQL4009
Message Text: Index created for table &1
Cause Text: A temporary index was built to access rows from the table for one of the following reasons:
  • Perform specified ordering/grouping criteria.
  • Perform specified join criteria.
The table number refers to the relative position of this table in the query.
Recovery Text: To improve performance, consider creating a permanent index if the query is run frequently. The query can be run in debug mode (STRDBG) to determine the specific reason the index was created and the key columns used when creating the index.
Note: If permanent index is created, it is possible the query optimizer may still choose to create a temporary index to access the rows from the table.