InnoDB System Variables system variables. See Section 5.1.9.1, “System Variable Privileges” . You can also use  --skip- innodb-adaptive-hash-index  at server startup to disable it. Disabling the adaptive hash index empties the hash table immediately. Normal operations can continue while the hash table is emptied, and executing queries that were using the hash table access the index B-trees directly instead. When the adaptive hash index is re-enabled, the hash table is populated again during normal operation. Partitions the adaptive hash index search system. Each index is bound to a specific partition, with each partition protected by a separate latch. The adaptive hash index search system is partitioned into 8 parts by default. The maximum setting is 512. For related information, see Section 15.5.3, “Adaptive Hash Index” . Permits  InnoDB  to automatically adjust the value of  innodb_thread_sleep_delay  up or down according to the current workload. Any nonzero value enables automated, dynamic adjustment of the  innodb_thread_sleep_delay  value, up to the maximum value specified in the innodb_adaptive_max_sleep_delay  option. The value represents the number of microseconds. This option can be useful in busy systems, with greater than 16  InnoDB  threads. (In practice, it is most valuable for MySQL systems with hundreds or thousands of simultaneous connections.) For more information, see Section 15.8.4, “Configuring Thread Concurrency for InnoDB” . 3217 • innodb_adaptive_max_sleep_delay • innodb_adaptive_hash_index_parts Command-Line Format --innodb-adaptive-hash-index-parts=# System Variable innodb_adaptive_hash_index_parts Scope Global Dynamic No SET_VAR  Hint Applies No Type Numeric Default Value 8 Minimum Value 1 Maximum Value 512 Command-Line Format --innodb-adaptive-max-sleep-delay=# System Variable innodb_adaptive_max_sleep_delay Scope Global Dynamic Yes SET_VAR  Hint Applies No Type Integer Default Value 150000 Minimum Value 0 Maximum Value 1000000