#
# innodb_instrument_semaphores
#
# save the initial value
SET @innodb_instrument_semaphores_global_saved = @@global.innodb_instrument_semaphores;
# default
SELECT @@global.innodb_instrument_semaphores;
@@global.innodb_instrument_semaphores
0

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

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

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

# restore the initial value
SET @@global.innodb_instrument_semaphores = @innodb_instrument_semaphores_global_saved;
# End of test