Another method of Metamorph index optimization is automatically, via
chkind daemon, and is enabled by default. This is a
process that runs automatically in the background (as part of the
database monitor), and periodically checks how out-of-date Metamorph
indexes are. When an index reaches a certain (configurable) threshold
of "staleness", it is re-optimized. See here
for more details on
chkind and its configuration.