Concern with CHECK TABLE on large InnoDB 24x7 table,
According to the MySQL BOL, CHECK TABLE blocks other threads on the table.


  When running CHECK TABLE on large InnoDB tables, other threads may be
  blocked during CHECK TABLE execution. To avoid timeouts, the semaphore
  wait threshold (600 seconds) is extended by 2 hours (7200 seconds) for
  CHECK TABLE operations. If InnoDB detects semaphore waits of 240
  seconds or more, it starts printing InnoDB monitor output to the error
  log. If a lock request extends beyond the semaphore wait threshold,
  InnoDB aborts the process. To avoid the possibility of a semaphore
  wait timeout entirely, run CHECK TABLE QUICK instead of CHECK TABLE.


Thanks!