This is a command-line option for the
mysqld commands (arg: Required).
Do not defragment a single index more than this number of time per second.This controls the number of time defragmentation thread can request X_LOCK on an index. Defragmentation thread will check whether 1/defragment_frequency (s) has passed since it worked on this index last time, and put the index back to the queue if not enough time has passed. The actual frequency can only be lower than this given number.