Documentation Home
MySQL 8.0 Reference Manual
Related Documentation Download this Manual
PDF (US Ltr) - 44.9Mb
PDF (A4) - 44.9Mb
PDF (RPM) - 40.6Mb
HTML Download (TGZ) - 10.5Mb
HTML Download (Zip) - 10.6Mb
HTML Download (RPM) - 9.1Mb
Man Pages (TGZ) - 205.8Kb
Man Pages (Zip) - 308.3Kb
Info (Gzip) - 3.9Mb
Info (Zip) - 3.9Mb
Excerpts from this Manual

MySQL 8.0 Reference Manual  /  ...  /  Combining Group Replication Versions

18.6.2.2 Combining Group Replication Versions

When you upgrade an online group, you might need to run different versions of MySQL on members in the group at the same time. Depending on the changes made between the versions of MySQL, you could encounter incompatibilities. For example, if a feature has been deprecated between major versions then combining the versions in a group might cause members which rely on the deprecated feature to fail. This section describes the best practices for combining members running different versions of MySQL in the same group.

Group Replication is versioned according to the server version which the plugin was bundled with, for example if a member is running MySQL 5.7.19 then that is the version of the plugin. This version number is critical when upgrading a group, and specifically at the time of joining members to a group. See Section 2.1.1, “Which MySQL Version and Distribution to Install”.

To check the version of MySQL on a group member issue:

SELECT MEMBER_HOST,MEMBER_PORT,MEMBER_VERSION FROM performance_schema.replication_group_members;
+-------------+-------------+----------------+
| member_host | member_port | member_version |
+-------------+-------------+----------------+
| example.com |	   3306     |   8.0.13	     |
+-------------+-------------+----------------+

The rules for combining members in a group with different major versions are:

  • You cannot join a member to a group when it is running an older major version than the major version which the existing group members are running. For example if you have a group with members running MySQL version 8.0, you cannot add a member which is running an older version such as MySQL version 5.7.

  • You can join a member to group if it is running a newer major version than the major version which the existing group members are running. For example if you have a group with members running MySQL 5.7, you can add a member running MySQL version 8.0, but it remains in read-only mode. Writing to this member while there are read-write members running an older MySQL version is dangerous and must be avoided.

The rules for combining members in a group with different minor versions are:

  • You can add members running a newer or older minor version to a group, they are able to do writes. In a single-primary group, added members default to being read-only.


User Comments
User comments in this section are, as the name implies, provided by MySQL users. The MySQL documentation team is not responsible for, nor do they endorse, any of the information provided here.
Sign Up Login You must be logged in to post a comment.