Manual Index Optimization via CREATE METAMORPH INDEX

A Metamorph index may be optimized manually simply by re-issuing the same CREATE METAMORPH [INVERTED|COUNTER] INDEX ... statement that was used to create it. Instead of producing an error noting that the index already exists - as would happen with regular or inverted indexes - the Metamorph index is re-optimized. (If the index is already fully optimized, the statement returns success immediately.)

Note that the ALTER INDEX statement (here) is an easier method of optimizing indexes.