SET @start_global_value = @@global.old_alter_table;
SELECT @start_global_value;
@start_global_value
DEFAULT
select @@global.old_alter_table;
@@global.old_alter_table
DEFAULT
select @@session.old_alter_table;
@@session.old_alter_table
DEFAULT
show global variables like 'old_alter_table';
Variable_name	Value
old_alter_table	DEFAULT
show session variables like 'old_alter_table';
Variable_name	Value
old_alter_table	DEFAULT
select * from information_schema.global_variables where variable_name='old_alter_table';
VARIABLE_NAME	VARIABLE_VALUE
OLD_ALTER_TABLE	DEFAULT
select * from information_schema.session_variables where variable_name='old_alter_table';
VARIABLE_NAME	VARIABLE_VALUE
OLD_ALTER_TABLE	DEFAULT
set global old_alter_table=1;
set session old_alter_table=1;
select @@global.old_alter_table;
@@global.old_alter_table
COPY
select @@session.old_alter_table;
@@session.old_alter_table
COPY
show global variables like 'old_alter_table';
Variable_name	Value
old_alter_table	COPY
show session variables like 'old_alter_table';
Variable_name	Value
old_alter_table	COPY
select * from information_schema.global_variables where variable_name='old_alter_table';
VARIABLE_NAME	VARIABLE_VALUE
OLD_ALTER_TABLE	COPY
select * from information_schema.session_variables where variable_name='old_alter_table';
VARIABLE_NAME	VARIABLE_VALUE
OLD_ALTER_TABLE	COPY
set global old_alter_table=2;
set session old_alter_table=2;
select @@global.old_alter_table;
@@global.old_alter_table
INPLACE
select @@session.old_alter_table;
@@session.old_alter_table
INPLACE
show global variables like 'old_alter_table';
Variable_name	Value
old_alter_table	INPLACE
show session variables like 'old_alter_table';
Variable_name	Value
old_alter_table	INPLACE
select * from information_schema.global_variables where variable_name='old_alter_table';
VARIABLE_NAME	VARIABLE_VALUE
OLD_ALTER_TABLE	INPLACE
select * from information_schema.session_variables where variable_name='old_alter_table';
VARIABLE_NAME	VARIABLE_VALUE
OLD_ALTER_TABLE	INPLACE
set global old_alter_table=3;
set session old_alter_table=3;
select @@global.old_alter_table;
@@global.old_alter_table
NOCOPY
select @@session.old_alter_table;
@@session.old_alter_table
NOCOPY
show global variables like 'old_alter_table';
Variable_name	Value
old_alter_table	NOCOPY
show session variables like 'old_alter_table';
Variable_name	Value
old_alter_table	NOCOPY
select * from information_schema.global_variables where variable_name='old_alter_table';
VARIABLE_NAME	VARIABLE_VALUE
OLD_ALTER_TABLE	NOCOPY
select * from information_schema.session_variables where variable_name='old_alter_table';
VARIABLE_NAME	VARIABLE_VALUE
OLD_ALTER_TABLE	NOCOPY
set global old_alter_table=4;
set session old_alter_table=4;
select @@global.old_alter_table;
@@global.old_alter_table
INSTANT
select @@session.old_alter_table;
@@session.old_alter_table
INSTANT
show global variables like 'old_alter_table';
Variable_name	Value
old_alter_table	INSTANT
show session variables like 'old_alter_table';
Variable_name	Value
old_alter_table	INSTANT
select * from information_schema.global_variables where variable_name='old_alter_table';
VARIABLE_NAME	VARIABLE_VALUE
OLD_ALTER_TABLE	INSTANT
select * from information_schema.session_variables where variable_name='old_alter_table';
VARIABLE_NAME	VARIABLE_VALUE
OLD_ALTER_TABLE	INSTANT
set global old_alter_table=1.1;
ERROR 42000: Incorrect argument type to variable 'old_alter_table'
set global old_alter_table=1e1;
ERROR 42000: Incorrect argument type to variable 'old_alter_table'
set global old_alter_table="foo";
ERROR 42000: Variable 'old_alter_table' can't be set to the value of 'foo'
SET @@global.old_alter_table = @start_global_value;
SELECT @@global.old_alter_table;
@@global.old_alter_table
DEFAULT