Oracle 5.0 Reference Manual page 1548

• Durability of commits.
is no guarantee that logs are flushed to disk on commit.
• Replication.
17.1.5.7. Limitations Relating to Performance in MySQL Cluster
The following performance issues are specific to or especially pronounced in MySQL Cluster:
• Range scans.
engine; it is also relatively more expensive to do many range scans than it is with either
InnoDB.
• Reliability of
completely tested or officially supported. This may result in nonoptimal query plans in some cases.
If necessary, you can employ
Section 13.2.8.3, "Index Hint
• Unique hash indexes.
accessing a table if
17.1.5.8. Issues Exclusive to MySQL Cluster
The following are limitations specific to the
• 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
• Adding and dropping of data nodes.
possible. In such cases, the entire cluster must be restarted.
• Backup and restore between architectures.
backup and restore between different architectures. For example, you cannot back up a cluster
running on a big-endian platform and then restore from that backup to a cluster running on a little-
endian system. (Bug #19255)
• Online schema changes.
accomplished using
not support autodiscovery of such changes. (However, you can import or create a table that
uses a different storage engine, and then convert it to
ENGINE=NDBCLUSTER. In such a case, you must issue a
cluster to pick up the change.)
• Binary logging.
MySQL Cluster has the following limitations or restrictions with regard to binary logging:
•
sql_log_bin
operations.
• MySQL Cluster cannot produce a binlog for tables having
Known Limitations of MySQL Cluster
There are no durable commits on disk. Commits are replicated, but there
Replication is not supported.
Note
See Section 17.1.5.3, "Limits Relating to Transaction Handling in MySQL
Cluster", for more information relating to limitations on transaction handling in
NDB.
There are query performance issues due to sequential access to the
Records in range.
USE INDEX
Syntax", for more information on how to do this.
Unique hash indexes created with
is given as part of the key.
NULL
The following issues relate to physical architecture of cluster hosts:
or other clients that may be accessing the cluster's SQL nodes.
It is not possible to make online schema changes such as those
ALTER TABLE
[494] has no effect on data operations; however, it is supported for schema
The
Records in range
or
FORCE INDEX
storage engine:
NDBCLUSTER
Online adding or dropping of data nodes is not currently
It is also not possible to perform a Cluster
or INDEX, as the
CREATE
NDB
FLUSH TABLES
1528
statistic is available but is not
to alter the execution plan. See
cannot be used for
USING HASH
engine does
NDB Cluster
using
ALTER TABLE tbl_name
statement to force the
columns but no primary key.
BLOB
storage
NDB
or
MyISAM