Percona XtraDB Cluster 5.7.16-27.19

Percona announces the release of Percona XtraDB Cluster 5.7.16-27.19 on December 15, 2016. Binaries are available from the downloads section or our software repositories.

Percona XtraDB Cluster 5.7.16-27.19 is now the current release, based on the following:

All Percona software is open-source and free.

Deprecated

  • The following encryption modes are now deprecated:
    • encrypt=1
    • encrypt=2
    • encrypt=3

The default is encrypt=0 with encryption disabled. The recommended mode now is the new encrypt=4, which uses SSL files generated by MySQL.

For more information, see Encrypting PXC Traffic.

New Features

  • Added encrypt=4 mode for SST encryption that uses SSL files generated by MySQL. Modes 1, 2, and 3 are now deprecated.
  • ProxySQL assisted maintenance mode that enables you to take a node down without adjusting ProxySQL manually. The mode is controlled using the pxc_maint_mode variable, which can be set to one of the following values:
    • DISABLED: This is the default state that tells ProxySQL to route traffic to the node as usual.
    • SHUTDOWN: This state is set automatically when you initiate node shutdown.
    • MAINTENANCE: You can change to this state if you need to perform maintenance on a node without shutting it down.

For more information, see Assisted Maintenance Mode.

  • Simplified SSL configuration for Galera/SST traffic with pxc-encrypt-cluster-traffic option, which auto-configures SSL encryption.

For more information, see SSL Automatic Configuration.

  • Added the wsrep_flow_control_interval status variable that displays the lower and upper limits of the flow control system used for the Galera receive queue.

Fixed Bugs

  • Optimized IST donor selection logic to avoid SST. Child processes are now cleaned-up and node state is resumed if SST fails.
  • Added init.ok to the list of files that do not get removed during SST.
  • Fixed error with ASIO library not acknowledging an EPOLLIN event when building Galera.
  • Fixed stalling of DML workload on slave node caused by FLUSH TABLE executed on the master.
    For more information, see 1629296.
  • Fixed super_read_only to not apply to Galera replication applier.
    For more information, see 1634295.
  • Redirected netcat output to stdout to avoid it in the log.
    For more information, see 1625968.
  • Enabled replication of ALTER USER statements.
    For more information, see 1376269.
  • Changed the wsrep_max_ws_rows variable to ignore non-replicated write-sets generated by DML action on temporary tables (explict or implicit).
    For more information, see 1638138.
  • Fixed SST to fail with an error if SSL is not supported by socat, instead of switching to unencrypted mode.
  • Fixed SST with SSL to auto-generate a 2048-bit dhparams file for versions of socat before 1.7.3. These older versions use 512-bit dhparams file by default that gets rejected by newer clients with dh key too small error.
  • PXC-731: Changed the wsrep_cluster_name variable to read-only, because changing it dynamically leads to high overhead.
    For more information, see 1620439.
  • PXC-732: Improved error message when any of the SSL files required for SST are missing.
  • PXC-735: Fixed SST to fail with an error when netcat is used (transferfmt=nc) with SSL encryption (encrypt set to 2, 3 or 4), instead of silently switching to unencrypted mode.
  • Fixed faulty switch case that caused cluster to stall when the repl.commit_order variable was set to 2 (LOCAL_OOOC mode that should allow out-of-order committing for local transactions).

Help us improve our software quality by reporting any bugs you encounter using our bug tracking system. As always, thanks for your continued support of Percona!