CREATE TABLE Statement relatively small cost to write performance. Beginning with NDB 8.0.19, 1 is the default for  READ_BACKUP , and the default for  ndb_read_backup  is  ON  (previously, read from any replica was disabled by default). You can set  READ_BACKUP  for an existing table online, using an  ALTER TABLE  statement similar to one of those shown here: ALTER TABLE ... ALGORITHM=INPLACE, COMMENT="NDB_TABLE=READ_BACKUP=1"; ALTER TABLE ... ALGORITHM=INPLACE, COMMENT="NDB_TABLE=READ_BACKUP=0"; For more information about the  ALGORITHM  option for  ALTER TABLE , see Section 23.5.11, “Online Operations with ALTER TABLE in NDB Cluster” . PARTITION_BALANCE : Provides additional control over assignment and placement of partitions. The following four schemes are supported: Only one LDM on each node stores a primary partition. Each partition is stored in the same LDM (same ID) on all nodes. Each node stores a single partition, which can be either a primary replica or a backup replica. Each partition is stored in the same LDM on all nodes. This is the setting used if  READ_BACKUP  is set to 1. These partitions can be primary or backup partitions. These partitions can be primary or backup partitions. These partitions can be primary or backup partitions. These partitions can be primary or backup partitions. PARTITION_BALANCE  is the preferred interface for setting the number of partitions per table. Using MAX_ROWS  to force the number of partitions is deprecated but continues to be supported for backward compatibility; it is subject to removal in a future release of MySQL NDB Cluster. (Bug #81759, Bug #23544301) FULLY_REPLICATED  controls whether the table is fully replicated, that is, whether each data node has a complete copy of the table. To enable full replication of the table, use  FULLY_REPLICATED=1 . This setting can also be controlled using the  ndb_fully_replicated  system variable. Setting it to  ON enables the option by default for all new  NDB  tables; the default is  OFF . The  ndb_data_node_neighbour system variable is also used for fully replicated tables, to ensure that when a fully replicated table is accessed, we access the data node which is local to this MySQL Server. 2595 1. FOR_RP_BY_NODE : One partition per node. 2. FOR_RA_BY_NODE : One partition per node group. 3. FOR_RP_BY_LDM : One partition for each LDM on each node; the default. 4. FOR_RA_BY_LDM : One partition per LDM in each node group. 5. FOR_RA_BY_LDM_X_2 : Two partitions per LDM in each node group. 6. FOR_RA_BY_LDM_X_3 : Three partitions per LDM in each node group. 7. FOR_RA_BY_LDM_X_4 : Four partitions per LDM in each node group.