Changing GTID Mode on Online Servers • UUID:NUMBER : generate a GTID with the specified UUID:NUMBER. • New GTID : generate a GTID with an automatically generated number. Table 17.2 Valid Combinations of gtid_mode and gtid_next gtid_next AUTOMATIC binary log on gtid_next AUTOMATIC binary log off gtid_next ANONYMOUS gtid_next UUID:NUMBER gtid_mode OFF ANONYMOUS ANONYMOUS ANONYMOUS Error gtid_mode OFF_PERMISSIVE ANONYMOUS ANONYMOUS ANONYMOUS UUID:NUMBER gtid_mode ON_PERMISSIVE New GTID ANONYMOUS ANONYMOUS UUID:NUMBER gtid_mode ON New GTID ANONYMOUS Error UUID:NUMBER When the binary log is off and  gtid_next  is set to  AUTOMATIC , then no GTID is generated. This is consistent with the behavior of previous versions. This section describes how to enable GTID transactions, and optionally auto-positioning, on servers that are already online and using anonymous transactions. This procedure does not require taking the server offline and is suited to use in production. However, if you have the possibility to take the servers offline when enabling GTID transactions that process is easier. From MySQL 8.0.23, you can set up replication channels to assign a GTID to replicated transactions that do not already have one. This feature enables replication from a source server that does not use GTID- based replication, to a replica that does. If it is possible to enable GTIDs on the replication source server, as described in this procedure, use this approach instead. Assigning GTIDs is designed for replication source servers where you cannot enable GTIDs. For more information on this option, see Section 17.1.3.6, “Replication From a Source Without GTIDs to a Replica With GTIDs” . Before you start, ensure that the servers meet the following pre-conditions: The following procedure can be paused at any time and later resumed where it was, or reversed by jumping to the corresponding step of Section 17.1.4.3, “Disabling GTID Transactions Online” , the online procedure to disable GTIDs. This makes the procedure fault-tolerant because any unrelated issues that may appear in the middle of the procedure can be handled as usual, and then the procedure continued where it was left off. It is crucial that you complete every step before continuing to the next step. To enable GTID transactions: 17.1.4.2 Enabling GTID Transactions Online • All  servers in your topology must use MySQL 5.7.6 or later. You cannot enable GTID transactions online on any single server unless  all  servers which are in the topology are using this version. •All servers have  gtid_mode  set to the default value  OFF . Note SET @@GLOBAL.ENFORCE_GTID_CONSISTENCY = WARN; 3477 1. On each server, execute: