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There is always one SUMA (replication) thread. 

NoOfFragmentLogParts  should be set equal to the number of LDM threads used by ndbmtd , as determined by the setting for this parameter. This ratio should not be any greater than 4:1; a configuration in which this is the case is specifically disallowed. 

The number of LDM threads also determines the number of partitions used by an NDB  table that is not explicitly partitioned; this is the number of LDM threads times the number of data nodes in the cluster. (If ndbd  is used on the data nodes rather than ndbmtd , then there is always a single LDM thread; in this case, the number of partitions created automatically is simply equal to the number of data nodes. See Section 23.1.2, “NDB Cluster Nodes, Node Groups, Fragment Replicas, and Partitions” , for more information. 

Adding large tablespaces for Disk Data tables when using more than the default number of LDM threads may cause issues with resource and CPU usage if the disk page buffer is insufficiently large; see the description of the DiskPageBufferMemory  configuration parameter, for more information. 

The thread types are described later in this section (see ThreadConfig ). 

Setting this parameter outside the permitted range of values causes the management server to abort on startup with the error Error line number : Illegal value value  for parameter MaxNoOfExecutionThreads . 

For MaxNoOfExecutionThreads , a value of 0 or 1 is rounded up internally by NDB  to 2, so that 2 is considered this parameter’s default and minimum value. 

MaxNoOfExecutionThreads  is generally intended to be set equal to the number of CPU threads available, and to allocate a number of threads of each type suitable to typical workloads. It does not assign particular threads to specified CPUs. For cases where it is desirable to vary from the settings provided, or to bind threads to CPUs, you should use ThreadConfig  instead, which allows you to allocate each thread directly to a desired type, CPU, or both. 

The multithreaded data node process always spawns, at a minimum, the threads listed here: 

•1 local query handler (LDM) thread 

•1 receive thread 

