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log injector thread, which runs on each MySQL server and produces a binary log ( binlog ). This thread ensures that all changes in the cluster producing the binary log—and not just those changes that are effected through the MySQL Server—are inserted into the binary log with the correct serialization order. We refer to the MySQL source and replica servers as replication servers or replication nodes, and the data flow or line of communication between them as a replication channel . 

For information about performing point-in-time recovery with NDB Cluster and NDB Cluster Replication, see Section 23.6.9.2, “Point-In-Time Recovery Using NDB Cluster Replication” . 

NDB API replica status variables.  NDB API counters can provide enhanced monitoring capabilities on replica clusters. These counters are implemented as NDB statistics _slave  status variables, as seen in the output of SHOW STATUS , or in the results of queries against the Performance Schema session_status  or global_status  table in a mysql  client session connected to a MySQL Server that is acting as a replica in NDB Cluster Replication. By comparing the values of these status variables before and after the execution of statements affecting replicated NDB  tables, you can observe the corresponding actions taken on the NDB API level by the replica, which can be useful when monitoring or troubleshooting NDB Cluster Replication. Section 23.5.13, “NDB API Statistics Counters and Variables” , provides additional information. 

Replication from NDB to non-NDB tables.  It is possible to replicate NDB  tables from an NDB Cluster acting as the replication source to tables using other MySQL storage engines such as InnoDB  or MyISAM on a replica mysqld . This is subject to a number of conditions; see Replication from NDB to other storage engines, and Replication from NDB to a nontransactional storage engine, for more information. 

## 23.6.1 NDB Cluster Replication: Abbreviations and Symbols 

Throughout this section, we use the following abbreviations or symbols for referring to the source and replica clusters, and to processes and commands run on the clusters or cluster nodes: 

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