InnoDB System Variables Maximum size for the  InnoDB  change buffer, as a percentage of the total size of the buffer pool. You might increase this value for a MySQL server with heavy insert, update, and delete activity, or decrease it for a MySQL server with unchanging data used for reporting. For more information, see Section 15.5.2, “Change Buffer” . For general I/O tuning advice, see Section 8.5.8, “Optimizing InnoDB Disk I/O” . Whether  InnoDB  performs change buffering, an optimization that delays write operations to secondary indexes so that the I/O operations can be performed sequentially. Permitted values are described in the following table. Values may also be specified numerically. • innodb_change_buffering Maximum Value 50 Command-Line Format --innodb-change-buffering=value System Variable innodb_change_buffering Scope Global Dynamic Yes SET_VAR  Hint Applies No Type Enumeration Default Value all Valid Values none inserts deletes changes purges all Value Numeric Value Description none 0 Do not buffer any operations. inserts 1 Buffer insert operations. deletes 2 Buffer delete marking operations; strictly speaking, the writes that mark index records for later deletion during a purge operation. changes 3 Buffer inserts and delete-marking operations. purges 4 Buffer the physical deletion operations that happen in the background. Table 15.25 Permitted Values for innodb_change_buffering 3228