There is a little used option innodb_defragment that would make OPTIMIZE TABLE not rebuild the table as usual for InnoDB, but instead cause the index B-trees to be optimized in place.

This option uses excessive locking (exclusively locking index trees). It never covered SPATIAL INDEX or FULLTEXT INDEX. Storage space was never reclaimed.

Because this option is not particularly useful and causes a maintenance burden (last, in MDEV-30400 when the B-tree cursors were refactored), I think that it is best to deprecate it, to give advance notice of its future removal.

The following parameters will be deprecated:

• innodb_defragment
• innodb_defragment_n_pages
• innodb_defragment_stats_accuracy
• innodb_defragment_fill_factor_n_recs
• innodb_defragment_fill_factor
• innodb_defragment_frequency