SQL4014 - &1 join column pair(s) are used for this join position

SQL4014
Message Text: &1 join column pair(s) are used for this join position
Cause Text: The query optimizer may choose to process join predicates as either join selection or row selection. The join predicates used in join selection are determined by the final join order and the index used. This message indicates how many join column pairs were processed as join selection at this join position. Message SQL4015 provides detail on which columns comprise the join column pairs.

If 0 join column pairs were specified then index scan-key row positioning with row selection was used instead of join selection.
Recovery Text: If fewer join pairs are used at a join position than expected, it is possible no index exists which has keys matching the desired join columns. Try creating an index whose keys match the join predicates.

If 0 join column pairs were specified then index scan-key row positioning was used. Index scan-key row positioning is normally a good performing option. Message SQL4011 provides more information about index scan-key row positioning.