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MySQL 8.0 Reference Manual  /  ...  /  Upgrading and Downgrading NDB Cluster

22.2.8 Upgrading and Downgrading NDB Cluster

This section provides information about NDB Cluster software and table file compatibility between different NDB Cluster 8.0 releases with regard to performing upgrades and downgrades as well as compatibility matrices and notes. You are expected already to be familiar with installing and configuring an NDB Cluster prior to attempting an upgrade or downgrade. See Section 22.3, “Configuration of NDB Cluster”.


Only compatibility between MySQL versions with regard to NDBCLUSTER is taken into account in this section, and there are likely other issues to be considered. As with any other MySQL software upgrade or downgrade, you are strongly encouraged to review the relevant portions of the MySQL Manual for the MySQL versions from which and to which you intend to migrate, before attempting an upgrade or downgrade of the NDB Cluster software. See Section 2.11, “Upgrading MySQL”.

Known Issues.  The following issues are known to occur when upgrading to or between NDB 8.0 releases:

  • Online downgrades from NDB 8.0.14 to previous releases are not supported. Tables created in NDB 8.0.14 are not backwards compatible with previous releases. This is due to a change in usage of the extra metadata property implemented by NDB tables to provide full support for the MySQL data dictionary.

    For more information, see NDB table extra metadata changes. See also Chapter 14, MySQL Data Dictionary.

  • Distributed privileges shared between MySQL servers as implemented in prior release series (see Distributed MySQL Privileges for NDB Cluster) are not supported in NDB Cluster 8.0. When started, the mysqld supplied with NDB 8.0.16 and later checks for the existence of any grant tables which use the NDB storage engine; if it finds any, it creates local copies (shadow tables) of these using InnoDB. This is true for each MySQL server connected to NDB Cluster. After this has been performed on all MySQL servers acting as NDB Cluster SQL nodes, the NDB grant tables may be safely removed using the ndb_drop_table utility supplied with the NDB Cluster distribution. (It is safe to retain the NDB grant tables, but they are not used for access control and are effectively ignored.) For more information about the MySQL privileges system used in NDB 8.0, see Section 6.2.3, “Grant Tables”.