#
# innodb_disallow_writes
#
# save the initial value
SET @innodb_disallow_writes_global_saved = @@global.innodb_disallow_writes;
# default
SELECT @@global.innodb_disallow_writes;
@@global.innodb_disallow_writes
0

# scope
SELECT @@session.innodb_disallow_writes;
ERROR HY000: Variable 'innodb_disallow_writes' is a GLOBAL variable
SET @@global.innodb_disallow_writes=OFF;
SELECT @@global.innodb_disallow_writes;
@@global.innodb_disallow_writes
0
SET @@global.innodb_disallow_writes=ON;
SELECT @@global.innodb_disallow_writes;
@@global.innodb_disallow_writes
1

# valid values
SET @@global.innodb_disallow_writes='OFF';
SELECT @@global.innodb_disallow_writes;
@@global.innodb_disallow_writes
0
SET @@global.innodb_disallow_writes=ON;
SELECT @@global.innodb_disallow_writes;
@@global.innodb_disallow_writes
1
SET @@global.innodb_disallow_writes=default;
SELECT @@global.innodb_disallow_writes;
@@global.innodb_disallow_writes
0

# invalid values
SET @@global.innodb_disallow_writes=NULL;
ERROR 42000: Variable 'innodb_disallow_writes' can't be set to the value of 'NULL'
SET @@global.innodb_disallow_writes='junk';
ERROR 42000: Variable 'innodb_disallow_writes' can't be set to the value of 'junk'

# restore the initial value
SET @@global.innodb_disallow_writes = @innodb_disallow_writes_global_saved;
# End of test