MySQL :: MySQL 8.3 Reference Manual :: 1.3 What Is New in MySQL 8.3
This section summarizes what has been added to, deprecated in, and removed from MySQL 8.3. A companion section lists MySQL server options and variables that have been added, deprecated, or removed in MySQL 8.3; see Section 1.4, “Server and Status Variables and Options Added, Deprecated, or Removed in MySQL 8.3”.
MySQL Replication: tagged GTIDs. The format of global transaction identifiers (GIDs) used in MySQL Replication and Group Replication has been extended to enable identification of groups of transactions, making it possible to assign a unique name to the GTIDs which belong to a specific group of transactions. For example, transactions containing data operations can easily be distinguished from those arising from administrative operations simply by comparing their GTIDs.
The new GTID format is UUID:TAG:NUMBER, where TAG is a string of up to 8 characters, which is enabled by setting the value of the gtid_next system variable to AUTOMATIC:TAG, added in this release (see the description of the variable for tag format and other information). This tag persists for all transactions originating in the current session (unless changed using SET gtid_next), and is applied at commit time for such transactions, or, when using Group Replication, at certification time. It is also possible to set gtid_next to UUID:TAG:NUMBER to set the UUID of a single transaction to an arbitrary value, along with assigning it a custom tag. The assignments of UUID and NUMBER are otherwise unchanged from previous MySQL releases. In either case, the user is responsible for making sure that the tag is unique to a given replication topology.
