MySQL NDB Cluster has great support for online (inplace) schema
changes, but it is still sometimes necessary to perform an
ALTER TABLE. These are relatively
expensive to make as the entire table is copied into a new table
which eventually replace the old table.
One example where a copying
ALTER TABLE is required
is when upgrading from MySQL NDB Cluster 7.2 or earlier to MySQL
NDB Cluster 7.3 or later. The format used for temporal columns
changed between these version (corresponding to MySQL Server 5.5
to 5.6). In order to take advantage of the new temporal format, a
table rebuild is required.
Note: Support for the old temporal format has been removed in MySQL 8.0. So, you must …[Read more]