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Dynamic buffer space (in bytes) for key and attribute data allocated to each data node. 

• TransactionMemory 

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This parameter determines the memory (in bytes) allocated for transactions on each data node. Setting of transaction memory can be handled in any one of the three ways listed here: 

•A number of configuration parameters are incompatible with TransactionMemory . If any of these are set, transaction memory is calculated as it was previous to NDB 8.0.19. You should be aware that it is not possible to set any of these parameters concurrently with TransactionMemory ; if you attempt to do so, the management server is unable to start (see Parameters incompatible with TransactionMemory). 

•If TransactionMemory  is set, this value is used for determining transaction memory. 

•If neither any incompatible parameters are set nor TransactionMemory  is set, transaction memory is set by NDB  to 10% of the value of the DataMemory  configuration parameter. 

Parameters incompatible with TransactionMemory.  The following parameters cannot be used concurrently with TransactionMemory  and are deprecated as of NDB 8.0.19: 

• MaxNoOfConcurrentIndexOperations 

• MaxNoOfFiredTriggers 

• MaxNoOfLocalOperations 

• MaxNoOfLocalScans 

Explicitly setting any of the parameters just listed when TransactionMemory  has also been set in the cluster configuration file ( config.ini ) keeps the management node from starting. 

For more information regarding resource allocation in NDB Cluster data nodes, see Section 23.3.3.13, “Data Node Memory Management” . 

Scans and buffering.  There are additional [ndbd]  parameters in the Dblqh  module (in ndb/src/kernel/blocks/Dblqh/Dblqh.hpp ) that affect reads and updates. These include ZATTRINBUF_FILESIZE , set by default to 10000 × 128 bytes (1250KB) and ZDATABUF_FILE_SIZE , set by default to 10000*16 bytes (roughly 156KB) of buffer space. To date, there have been neither any 

