InnoDB System Variables Dynamic Yes SET_VAR  Hint Applies No Type Boolean Default Value OFF Command-Line Format --innodb-purge-batch-size=# System Variable innodb_purge_batch_size Scope Global Dynamic Yes SET_VAR  Hint Applies No Type Integer Default Value 300 Minimum Value 1 Maximum Value 5000 Command-Line Format --innodb-purge-threads=# System Variable innodb_purge_threads Scope Global Dynamic No SET_VAR  Hint Applies No Type Integer Default Value 4 Minimum Value 1 3274 Enabling this option causes MySQL to write DDL logs to  stderr . For more information, see Viewing DDL Logs. Defines the number of undo log pages that purge parses and processes in one batch from the history list. In a multithreaded purge configuration, the coordinator purge thread divides innodb_purge_batch_size  by  innodb_purge_threads  and assigns that number of pages to each purge thread. The  innodb_purge_batch_size  variable also defines the number of undo log pages that purge frees after every 128 iterations through the undo logs. The  innodb_purge_batch_size  option is intended for advanced performance tuning in combination with the  innodb_purge_threads  setting. Most users need not change  innodb_purge_batch_size from its default value. For related information, see Section 15.8.9, “Purge Configuration” . • innodb_purge_batch_size • innodb_purge_threads