6.7 Known Issues and Limitations of ndbmemcache

This section provides information about known issues with and design limitations of the Memcache API for MySQL Cluster.

Problems with AUTO_INCREMENT ndbmemcache bypasses the NDB 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.

Fractional seconds.  Beginning with MySQL Cluster NDB 7.2.3, ndbmemcache supports the use of fractional seconds with the TIME, DATE, and DATETIME data types as implemented in MySQL 5.6.4 and later. ndbmemcache in previous versions of MySQL Cluster does not support fractional seconds. (Bug #16593493)