Category Archives: Replication

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.…

Group Replication: Preventing stale reads on primary fail-over!

This is a follow up post about the new consistency option of Group Replication group_replication_consistency. We recommend that you first read this post to get an overview of scenarios that can be addressed with this solution.

A group replication cluster will automatically detect failures and adjust the view of the members that are active, i.e., the membership configuration.…

Group Replication – Consistency Levels

The MySQL Group Replication (GR) feature is a multi-primary update anywhere or single-primary replication plugin for MySQL with built-in conflict detection and resolution, automatic distributed recovery, and group membership.

Its goal it is to make high-availability (HA) simple with off-the-shelf hardware, not only to new applications but also existing ones – that was one of the motivations of the single-primary mode.…

How to manually decrypt an encrypted binary log file

The encrypted binary log file format introduced in MySQL version 8.0.14 was designed to allow a “manual” decryption of the file data when the value of the key that encrypted its file password is known.

Each encrypted binary (or relay) log file is composed by an encrypted binary log file header and the encrypted binary log content (the file data).…