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16.14.9 Limitations Relating to Disk Data Storage »
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16.14.8. Issues Exclusive to MySQL Cluster

The following are limitations specific to the NDBCLUSTER storage engine:

  • Machine architecture.  All machines used in the cluster must have the same architecture. That is, all machines hosting nodes must be either big-endian or little-endian, and you cannot use a mixture of both. For example, you cannot have a management node running on a PowerPC which directs a data node that is running on an x86 machine. This restriction does not apply to machines simply running mysql or other clients that may be accessing the cluster's SQL nodes.

  • Adding and dropping of data nodes.  Online adding or dropping of data nodes is not currently possible. In such cases, the entire cluster must be restarted.

  • Binary logging.  MySQL Cluster has the following limitations or restrictions with regard to binary logging:

    • SQL_LOG_BIN has no effect on data operations; however, it is supported for schema operations.

    • MySQL Cluster cannot produce a binlog for tables having BLOB columns but no primary key.

    • Only the following schema operations are logged in a cluster binlog which is not on the mysqld executing the statement:

      • CREATE TABLE

      • ALTER TABLE

      • DROP TABLE

      • CREATE DATABASE / CREATE SCHEMA

      • DROP DATABASE / DROP SCHEMA

      • CREATE TABLESPACE

      • ALTER TABLESPACE

      • DROP TABLESPACE

      • CREATE LOGFILE GROUP

      • ALTER LOGFILE GROUP

      • DROP LOGFILE GROUP

See also Section 16.14.10, “Limitations Relating to Multiple Cluster Nodes”.


User Comments

Posted by David Lotts on December 27 2007 8:02pm[Delete] [Edit]

Above it says: "Online schema changes. It is not possible to make online schema changes..."

In our experience with Version 5.0.45:
Sometimes it worked smoothly, but in one instance, we got a corrupted schema in one node. We were altering tables then switching one data node off then the other on, then more alterations. Not something you'd do in a production setting.

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