SET @save_gtid_ignore_duplicates= @@GLOBAL.gtid_ignore_duplicates;
SELECT @@GLOBAL.gtid_ignore_duplicates as 'must be zero because of default';
must be zero because of default
0
SELECT @@SESSION.gtid_ignore_duplicates  as 'no session var';
ERROR HY000: Variable 'gtid_ignore_duplicates' is a GLOBAL variable
SET GLOBAL gtid_ignore_duplicates= FALSE;
SET GLOBAL gtid_ignore_duplicates= DEFAULT;
SET GLOBAL gtid_ignore_duplicates= TRUE;
SELECT @@GLOBAL.gtid_ignore_duplicates;
@@GLOBAL.gtid_ignore_duplicates
1
SET GLOBAL gtid_ignore_duplicates = @save_gtid_ignore_duplicates;