Galera Cluster for MySQL 5.7.34 and 8.0.25 released

Codership is pleased to announce a new Generally Available (GA) release of the multi-master Galera Cluster for MySQL 5.7 and 8.0, consisting of MySQL-wsrep 5.7.34 (release notes, download) and MySQL-wsrep 8.0.25 (release notes, download) with Galera replication library 3.34 (release notes, download) implementing wsrep API version 25 and Galera replication library 4.9 (release notes, download) implementing wsrep API version 26. This release incorporates all changes to MySQL 5.7.34 and 8.0.25 respectively, adding a synchronous option for your MySQL High Availability solutions. We skipped releasing MySQL 8.0.24 because upstream released 8.0.25 fairly quickly with some bug fixes, so for a complete change log, it is advisable to also refer to the 8.0.24 release notes.

For the Galera replication library 3.34, we improved the handling of Incremental State Transfers (IST) to allow a resumption after the process is restarted. We have also added a new status variable, wsrep_apply_waits to count the number of times an applier thread had to wait for applying a write set (documentation). We improved performance around how the GCache uses the CPU during IST, and also improved GCS flow control write set replication when a node is in the Donor state. Overall, we improved reliability of the GCache.

In addition to everything included in Galera replication library 3.34, for Galera replication library 4.9 we improved the networking code to handle addresses that are already in use, and for streaming replication we ensure that write sets a respecting apply order more reliably. We also now expose socket.ssl_reload as a WSREP provider option when SSL is enabled.

In MySQL 5.7.34, State Snapshot Transfer (SST) scripts for rsync and xtrabackup-v2 now accept SSL configuration variables, and we deprecated the old variables. We now also do not purge the binary log when the server is started with --wsrep-recover, and we have disabled parallel apply to write sets for tables without primary keys (though we still always encourage you to have tables with primary keys). We now have a dependency on stunnel because we want to ensure support for rsync SST.

In addition to the above in MySQL 5.7.34, in MySQL 8.0.25 we have improved the reliability of CLONE SST as well. We have improved the metadata locks (MDL) and InnoDB locking to handle cluster-wide conflicts more gracefully. When we parallel apply a foreign key parent delete, we respect the apply order as well. Percona XtraBackup version 8.0.25-17.0 or higher is required to perform an XtraBackup based SST.

Ubuntu 16.04 LTS (Xenial) has reached the end of the regular maintenance period, so we will discontinue providing packages after this release.

We have decided to deprecate SUSE Linux Enterprise Server 12 and 15 going forward, and this will be the last release we make for SUSE Linux Enterprise Server. The reasoning behind this is simple: there is a weak usage pattern for this Linux distribution. Users are advised to continue using the binary tarball, or ask upstream to build packages for users.

As a reminder, MySQL 5.6 has reached End Of Life (EOL) so we do recommend that you upgrade to MySQL-wsrep 5.7. It is also why we have no builds for it this time. This will likely serve as the final reminder of this.