System Variables

The Twitter MySQL server maintains system variables that indicate how it is configured. System variables can be set at server startup using options on the command line or in an option file.

Name	Cmd-Line	Option file	System Var	Var Scope	Dynamic
max_statement_time	No	No	Yes	Session	Yes
minidump_dir	Yes	Yes	Yes	Global	No
protocol_mode	Yes	Yes	Yes	Both	Yes
super_only	Yes	Yes	Yes	Global	Yes

--max_statement_time=value

The number of milliseconds to wait for a statement to execute, after which it is interrupted. This timeout applies only to top-level statements.

Variable Name	max_statement_time
Variable Scope	Session
Dynamic Variable	Yes
Type	Numeric
Default	0
Valid Values	[0, (2^64)-1]

--minidump_dir=value

The name of the directory where minidumps are created. The default value is initialized tmpdir.

Variable Name	minidump_dir
Variable Scope	Global
Dynamic Variable	No
Type	String
Default	@@tmpdir

--protocol-mode=value[,value[,value...]]

The current server protocol mode, which can be set dynamically.

Command-Line Format	--protocol-mode=name
Option-File Format	protocol-mode
Option Sets Variable	Yes, protocol_mode
Variable Name	protocol_mode
Variable Scope	Global, Session
Dynamic Variable	Yes
Type	Set
Default	""
Valid Values	MINIMAL_OBJECT_NAMES_IN_RESULT_SET_METADATA Minimal metadata includes only the column name in the Result Set Metadata.

--super-only

Whether the server permits non-superusers to execute statements.

Command-Line Format	--super-only
Option-File Format	super_only
Option Sets Variable	Yes, super_only
Variable Name	super_only
Variable Scope	Global
Dynamic Variable	Yes
Type	Numeric
Default	0
Valid Values	0 Any user can execute statements. 1 Only superusers can execute statements.