The following performance issues are specific to or especially pronounced in NDB Cluster:
Range scans.
There are query performance issues due to sequential
access to the NDB storage
engine; it is also relatively more expensive to do many
range scans than it is with either
MyISAM or InnoDB.
Reliability of Records in range.
The Records in range statistic is
available but is not completely tested or officially
supported. This may result in nonoptimal query plans in
some cases. If necessary, you can employ USE
INDEX or FORCE INDEX to alter
the execution plan. See Section 8.9.3, “Index Hints”, for
more information on how to do this.
Unique hash indexes.
Unique hash indexes created with USING
HASH cannot be used for accessing a table if
NULL is given as part of the key.