Category Archives: Replication

Configuring the communication protocol in Group Replication

In a previous blog post we presented the message fragmentation functionality that you can use starting with MySQL Group Replication 8.0.16.

No group member can have a version < 8.0.16 if you wish to use message fragmentation in a group. MySQL 8.0.16 also ships with a new Group Replication concept to help you ensuring backwards compatibility: the group’s communication protocol.…

Enhanced support for large transactions in Group Replication

MySQL 8.0.16 is out and it enhances Group Replication as usual. For example, the group_replication_exit_state_action system variable has a new default value, and members that the group expels can now automatically try to rejoin. This post presents a new feature MySQL 8.0.16 brings to Group Replication: message fragmentation.…

MySQL 8.0.16 Replication Enhancements

MySQL 8.0.16 has been released last Thursday. In it, you can find some new replication features. Here is a quick summary. Follow-up blog posts will provide details about these features.

  • Large Messages Fragmentation Layer for Group Replication. Tiago Vale’s work, introduces message fragmentation to the Group Communication Framework.

Group Replication – Consistent Reads Deep Dive

On previous posts about Group Replication consistency we:

  1. introduced consistency levels;
  2. explained how to configure the primary failover consistency;
  3. presented how to configure transaction consistency levels to achieve the consistency required by your applications.

In blog 3. we presented the consistency levels: EVENTUAL, BEFORE, AFTER and BEFORE_AND_AFTER; their scopes: SESSION, GLOBAL; and their context: whether they only impact the ongoing transaction or all concurrent transactions.…

IPv6 support in Group Replication

In 8.0.14, we add to Group Replication (GR) the ability to use IPv6 in all of its network-related configuration parameters. This means that now you can take advantage of this technology and “rock” those billion addresses using MySQL Group Replication.

What’s New

When you operate a Group Replication group, some variables use network addresses, mainly:

  • group_replication_local_address;
  • group_replication_ip_whitelist
  • group_replication_group_seeds;
  • group_replication_force_members.

Server version in the binary log

Replication topologies, whether master-slave or group replication setups, may be composed of servers using different MySQL versions.

In MySQL 8.0.14, each transaction’s immediate and original server versions are now visible in the binary log as session variables. These two new variables, fully managed by the replication infrastructure, are used to support cross-version replication by transmitting the MySQL server release numbers associated with each transaction through the replication topology:

  • original_server_version stores the MySQL Server release number of the server where a transaction was originally committed (for example, 80014 for a MySQL 8.0.14 server instance).

Group Replication now interacts with the Group Communication Engine more efficiently

MySQL 8.0.14 comes with a plethora of new features. Some of the new Group Replication features have userfacing options, some impact user-facing options, and others stay completely under the hood. This post will present one of the under-the-hood changes in MySQL 8.0.14: the way the Group Replication layer interacts with the underlying Group Communication Engine layer, XCom.…