InnoDB System Variables growth. Actual percentages may vary. The  innodb_fill_factor  setting is interpreted as a hint rather than a hard limit. An  innodb_fill_factor  setting of 100 leaves 1/16 of the space in clustered index pages free for future index growth. innodb_fill_factor  applies to both B-tree leaf and non-leaf pages. It does not apply to external pages used for  TEXT  or  BLOB  entries. For more information, see Section 15.6.2.3, “Sorted Index Builds” . Write and flush the logs every  N  seconds.  innodb_flush_log_at_timeout  allows the timeout period between flushes to be increased in order to reduce flushing and avoid impacting performance of binary log group commit. The default setting for  innodb_flush_log_at_timeout  is once per second. • innodb_flush_log_at_timeout • innodb_flush_log_at_trx_commit •The default setting of 1 is required for full ACID compliance. Logs are written and flushed to disk at each transaction commit. Controls the balance between strict ACID compliance for commit operations and higher performance that is possible when commit-related I/O operations are rearranged and done in batches. You can achieve better performance by changing the default value but then you can lose transactions in a crash. 3243 Command-Line Format --innodb-flush-log-at-timeout=# System Variable innodb_flush_log_at_timeout Scope Global Dynamic Yes SET_VAR  Hint Applies No Type Integer Default Value 1 Minimum Value 1 Maximum Value 2700 Command-Line Format --innodb-flush-log-at-trx-commit=# System Variable innodb_flush_log_at_trx_commit Scope Global Dynamic Yes SET_VAR  Hint Applies No Type Enumeration Default Value 1 Valid Values 0 1 2