You can run 'ANALYZE
INDEX VALIDATE STRUCTURE' command on the affected indexes; each invocation of
this command creates a single row in the INDEX_STATS view.
This row is
overwritten by the next ANALYZE INDEX command, so copy the contents of the view
into a local table after each ANALYZE
The 'badness' of the index can then be
judged by the ratio of 'DEL_LF_ROWS' to 'LF_ROWS'
