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Percona XtraDB Cluster 8.0.25-15.1

Percona XtraDB Cluster 8.0.25-15.1 includes all of the features and bug fixes available in Percona Server for MySQL. See the corresponding release notes for Percona Server for MySQL 8.0.25-15 for more details on these changes.

Percona XtraDB Cluster (PXC) supports critical business applications in your public, private, or hybrid cloud environment. Our free, open source, enterprise-grade solution includes the high availability and security features your business requires to meet your customer expectations and business goals.

Release Highlights

A Non-Blocking Operation method for online schema changes in Percona XtraDB Cluster. This mode is similar to the Total Order Isolation (TOI) mode, whereas a data definition language (DDL) statement (for example, ALTER) is executed on all nodes in sync. The difference is that in the NBO mode, the DDL statement acquires a metadata lock that locks the table or schema at a late stage of the operation, which is a more efficient locking strategy.

Note that the NBO mode is a Tech Preview feature. We do not recommend that you use this mode in a production environment. For more information, see Non-Blocking Operations (NBO) method for Online Scheme Upgrades (OSU).

The notable changes and bug fixes introduced by Oracle MySQL include the following:

  • The sql_slave_skip_counter variable only counts the events in the uncompressed transaction payloads.

  • A possible deadlock occurred when system variables, read by different clients, were being updated and the binary log file was rotated.

  • Sometimes the aggregate function results could return values from a previous statement when using a prepared SELECT statement with a WHERE clause that is always false.

For more information, see the MySQL 8.0.24 Release Notes and the MySQL 8.0.25 Release Notes.

New Features

  • PXC-3265 Implements the Non-Blocking Operations (NBO) mode for an Online schema upgrade.

Bugs Fixed

  • PXC-3275: Fix the documented APT package list to match the packages listed in the Repo. (Thanks to user Hubertus Krogmann for reporting this issue)

  • PXC-3387: Performing an intermediate commit does not call wsrep commit hooks.

  • PXC-3449: Fix for missing dependencies which were carried out in replication writesets caused Galera to fail.

  • PXC-3589: Documentation: Updates in Percona XtraDB Cluster Limitations that the LOCK=NONE clause is no longer allowed in an INPLACE ALTER TABLE statement. (Thanks to user Brendan Byrd for reporting this issue)

  • PXC-3611: Fix that deletes any keyring.backup file if it exists for SST operation.

  • PXC-3608: Fix a concurrency issue that caused a server exit when attempting to read a foreign key.

  • PXC-3637: Changes the service start sequence to allow more time for mounting local or remote directories with large amounts of data. (Thanks to user Eric Gonyea for reporting this issue)

  • PXC-3679: Fix for SST failures after the update of socat to ‘1.7.4.0’.

  • PXC-3706: Fix adds a wait to wsrep_after_commit until the first thread in a group commit queue is available.

  • PXC-3729: Fix for conflicts when multiple applier threads execute certified transactions and are in High-Priority transaction mode.

  • PXC-3731: Fix for incorrect writes to the binary log when sql_log_bin=0.

  • PXC-3733: Fix to clean the WSREP transaction state if a transaction is requested to be re-prepared.