Some SQL statements relating to certain MySQL features produce
errors when used with NDB tables,
as described in the following list:
Temporary tables.
Temporary tables are not supported. Trying either to
create a temporary table that uses the
NDB storage engine or to
alter an existing temporary table to use
NDB fails with the error
Table storage engine 'ndbcluster' does not
support the create option 'TEMPORARY'.
Indexes and keys in NDB tables.
Keys and indexes on MySQL Cluster tables are subject to
the following limitations:
Column width.
Attempting to create an index on an
NDB table column whose width
is greater than 3072 bytes succeeds, but only
the first 3072 bytes are actually used for the
index. In such cases, a warning
Specified key was too long; max key
length is 3072 bytes is issued, and
a SHOW CREATE
TABLE statement shows the length of
the index as 3072.
TEXT and
BLOB columns.
You cannot create indexes on
NDB table columns
that use any of the
TEXT or
BLOB data types.
FULLTEXT indexes.
The NDB storage
engine does not support
FULLTEXT indexes, which are
possible for MyISAM tables
only.
However, you can create indexes on
VARCHAR columns of
NDB tables.
Prefixes.
There are no prefix indexes; only entire columns
can be indexed. (The size of an
NDB column index is always
the same as the width of the column in bytes, up
to and including 3072 bytes, as described
earlier in this section. Also see
Section 17.1.5.6, “Unsupported or Missing Features in MySQL Cluster”,
for additional information.)
BIT columns.
A BIT column
cannot be a primary key, unique key, or index,
nor can it be part of a composite primary key,
unique key, or index.
AUTO_INCREMENT columns.
Like other MySQL storage engines, the
NDB storage engine
can handle a maximum of one
AUTO_INCREMENT column per
table. However, in the case of a Cluster table
with no explicit primary key, an
AUTO_INCREMENT column is
automatically defined and used as a
“hidden” primary key. For this
reason, you cannot define a table that has an
explicit AUTO_INCREMENT
column unless that column is also declared using
the PRIMARY KEY option.
Attempting to create a table with an
AUTO_INCREMENT column that is
not the table's primary key, and using the
NDB storage engine,
fails with an error.
MySQL Cluster and geometry data types.
Geometry datatypes (WKT and
WKB) are supported in
NDB tables in MySQL
5.0. However, spatial indexes are not
supported.


User Comments
As of 5.1.23-ndb-6.3.8 two new session variables exist which allow NDB to create pseudo-temporary tables.
These tables will be visible to all user sessions and will be present until the cluster restarts.
ndb_table_no_logging=[1|0] controls weather tables created within that session will be REDO logged or checkpointed to disk. This makes the persistence of these NDB table behave similarly to MEMORY engine where are truncated on cluster restart.
ndb_table_temporary=[1|0] controls weather any schema file will be created in the cluster. This option behaves similarly to ndb_table_no_logging except that it will cause no schema file to be created, thus when the cluster restarts it will be completely removed.
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