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• gtid_mode 

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Controls whether GTID based logging is enabled and what type of transactions the logs can contain. You must have privileges sufficient to set global system variables. See Section 5.1.9.1, “System Variable Privileges” . enforce_gtid_consistency  must be set to ON  before you can set gtid_mode=ON . Before modifying this variable, see Section 17.1.4, “Changing GTID Mode on Online Servers” . 

Logged transactions can be either anonymous or use GTIDs. Anonymous transactions rely on binary log file and position to identify specific transactions. GTID transactions have a unique identifier that is used to refer to transactions. The different modes are: 

• OFF : Both new and replicated transactions must be anonymous. 

• OFF_PERMISSIVE : New transactions are anonymous. Replicated transactions can be either anonymous or GTID transactions. 

• ON_PERMISSIVE : New transactions are GTID transactions. Replicated transactions can be either anonymous or GTID transactions. 

• ON : Both new and replicated transactions must be GTID transactions. 

Changes from one value to another can only be one step at a time. For example, if gtid_mode  is currently set to OFF_PERMISSIVE , it is possible to change to OFF  or ON_PERMISSIVE  but not to ON . 

The values of gtid_purged  and gtid_executed  are persistent regardless of the value of gtid_mode . Therefore even after changing the value of gtid_mode , these variables contain the correct values. 

• gtid_next 

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