This section provides information about known issues with and design limitations of the Memcache API for NDB Cluster.
Problems with AUTO_INCREMENT.
ndbmemcache bypasses the
storage engine's mechanism for handling
AUTO_INCREMENT columns. This means that, when
you insert rows using ndbmemcache into a table having an
AUTO_INCREMENT column, this column is not
automatically updated. This can lead to duplicate key errors
when inserts are performed later using SQL in a MySQL client
application such as mysql.
To work around this issue, you can employ a sequence generator as described here.
Online schema changes not supported. The memcached daemon does not detect online schema changes; after making such changes, you must restart the memcached daemon before the updated schema can be used by your application.
Beginning with NDB 7.2.3, ndbmemcache supports the use of
fractional seconds with the
DATETIME data types as
implemented in MySQL 5.6.4 and later. ndbmemcache in previous
versions of NDB Cluster does not support fractional seconds.