InnoDB System Variables

InnoDB-related command options and system variables. Boolean system variables can be enabled at server startup by naming them, or disabled by using a --skip- prefix.

Name	Cmd-Line	Option file	System Var	Status Var	Var Scope	Dynamic
innodb_anticipatory_flushing	Yes	Yes	Yes	No	Global	Yes
innodb_flush_dirty_pages_age	Yes	Yes	Yes	No	Global	Yes
innodb_flush_neighbors	Yes	Yes	Yes	No	Global	Yes
innodb_free_extents_reservation_factor	Yes	Yes	Yes	No	Global	Yes
innodb_index_fill_factor	Yes	Yes	Yes	No	Global	Yes
innodb_index_page_split_mode	Yes	Yes	Yes	No	Both	Yes
innodb_reserve_free_extents	Yes	Yes	Yes	No	Global	Yes
innodb_segment_fill_factor	Yes	Yes	Yes	No	Global	Yes

innodb_anticipatory_flushing

Specifies whether the master thread will flush dirty pages from the buffer pool if there is I/O bandwidth available for background tasks.

Command-Line Format	--innodb_anticipatory_flushing
Option-File Format	innodb_anticipatory_flushing
Option Sets Variable	Yes, innodb_anticipatory_flushing
Variable Name	innodb_anticipatory_flushing
Variable Scope	Global
Dynamic Variable	Yes
Type	Boolean
Default	ON
Valid Values	ON, OFF

innodb_flush_dirty_pages_age

Minimum age (since the last flush) of pages to be flushed from the buffer pool if the number of dirty pages is below the maximum percentage.

Command-Line Format	--innodb_flush_dirty_pages_age
Option-File Format	innodb_flush_dirty_pages_age
Option Sets Variable	Yes, innodb_flush_dirty_pages_age
Variable Name	innodb_flush_dirty_pages_age
Variable Scope	Global
Dynamic Variable	Yes
Type	Numeric
Default	0 (OFF)
Valid Values	[0, 2^32]

innodb_flush_neighbors

Specifies whether flushing a page from the InnoDB buffer pool also flushes other dirty pages in the same extent.

Command-Line Format	--innodb_flush_neighbors
Option-File Format	innodb_flush_neighbors
Option Sets Variable	Yes, innodb_flush_neighbors
Variable Name	innodb_flush_neighbors
Variable Scope	Global
Dynamic Variable	Yes
Type	Boolean
Default	ON
Valid Values	ON, OFF

innodb_free_extents_reservation_factor

Percentage of a space size to reserve for operations that may cause more space to be used. If the resulting amount of free space (in extents) is not available, the operation is not allowed to proceed.

Command-Line Format	--innodb_free_extents_reservation_factor
Option-File Format	innodb_free_extents_reservation_factor
Option Sets Variable	Yes, innodb_free_extents_reservation_factor
Variable Name	innodb_free_extents_reservation_factor
Variable Scope	Global
Dynamic Variable	Yes
Type	Floating-point
Default	1.0
Valid Values	[0.0, 100.0]

innodb_index_fill_factor

Specifies the percentage of how much to fill a leaf page when inserting data, the remaining space being reserved to accommodate row expansion.

Command-Line Format	--innodb_index_fill_factor
Option-File Format	innodb_index_fill_factor
Option Sets Variable	Yes, innodb_index_fill_factor
Variable Name	innodb_index_fill_factor
Variable Scope	Global
Dynamic Variable	Yes
Type	Floating-point
Default	93.75
Valid Values	[0.0, 100.0]

innodb_index_page_split_mode

Specifies the index page split behavior. Currently, symmetric is always required and will be added if not stated.

Command-Line Format	--innodb_index_page_split_mode
Option-File Format	innodb_index_page_split_mode
Option Sets Variable	Yes, innodb_index_page_split_mode
Variable Name	innodb_index_page_split_mode
Variable Scope	Global, Session
Dynamic Variable	Yes
Type	Set
Default	""
Valid Values	symmetric Pages are always split roughly in the middle. upper Split point is possibly at or near the insertion point if a pattern of sequential inserts is detected in the right-most page of the index tree. lower Split point is possibly at or near the insertion point if a pattern of sequential inserts is detected in the left-most page of the index tree.

innodb_reserve_free_extents

Whether to reserve a certain percentage of a space size as free space for operations that might allocate several pages.

Command-Line Format	--innodb_reserve_free_extents
Option-File Format	innodb_reserve_free_extents
Option Sets Variable	Yes, innodb_reserve_free_extents
Variable Name	innodb_reserve_free_extents
Variable Scope	Global
Dynamic Variable	Yes
Type	Boolean
Default	ON
Valid Values	ON, OFF

innodb_segment_fill_factor

Specifies the percentage of space on a segment to be used, reserving the remainder as free space for future data growth.

Command-Line Format	--innodb_segment_fill_factor
Option-File Format	innodb_segment_fill_factor
Option Sets Variable	Yes, innodb_segment_fill_factor
Variable Name	innodb_segment_fill_factor
Variable Scope	Global
Dynamic Variable	Yes
Type	Floating-point
Default	87.50
Valid Values	[0.0, 100.00]