NDB API Statistics Counters and Variables | NDB_API_UK_OP_COUNT | 0 | | NDB_API_TABLE_SCAN_COUNT | 1 | | NDB_API_RANGE_SCAN_COUNT | 0 | | NDB_API_PRUNED_SCAN_COUNT | 0 | | NDB_API_SCAN_BATCH_COUNT | 0 | | NDB_API_READ_ROW_COUNT | 2 | | NDB_API_TRANS_LOCAL_READ_ROW_COUNT | 2 | | NDB_API_EVENT_DATA_COUNT | 0 | | NDB_API_EVENT_NONDATA_COUNT | 0 | | NDB_API_EVENT_BYTES_COUNT | 0 | +--------------------------------------------+----------------+ 60 rows in set (0.00 sec) Each  Ndb  object has its own counters. NDB API applications can read the values of the counters for use in optimization or monitoring. For multithreaded clients which use more than one  Ndb  object concurrently, it is also possible to obtain a summed view of counters from all  Ndb  objects belonging to a given  Ndb_cluster_connection . Four sets of these counters are exposed. One set applies to the current session only; the other 3 are global.  This is in spite of the fact that their values can be obtained as either session or global status variables in the  mysql  client . This means that specifying the  SESSION  or  GLOBAL  keyword with  SHOW STATUS  has no effect on the values reported for NDB API statistics status variables, and the value for each of these variables is the same whether the value is obtained from the equivalent column of the session_status  or the  global_status  table. Session counters relate to the  Ndb  objects in use by (only) the current session. Use of such objects by other MySQL clients does not influence these counts. In order to minimize confusion with standard MySQL session variables, we refer to the variables that correspond to these NDB API session counters as “ _session  variables” , with a leading underscore. This set of counters relates to the  Ndb  objects used by the replica SQL thread, if any. If this  mysqld does not act as a replica, or does not use  NDB  tables, then all of these counts are 0. We refer to the related status variables as “ _slave  variables”  (with a leading underscore). Injector counters relate to the  Ndb  object used to listen to cluster events by the binary log injector thread. Even when not writing a binary log,  mysqld  processes attached to an NDB Cluster continue to listen for some events, such as schema changes. We refer to the status variables that correspond to NDB API injector counters as “ _injector  variables” (with a leading underscore). This set of counters relates to all  Ndb  objects currently used by this  mysqld . This includes all MySQL client applications, the replica SQL thread (if any), the binary log injector, and the  NDB  utility thread. We refer to the status variables that correspond to these counters as “global variables”  or “ mysqld -level variables” . 4512 • Session counters (session specific) • Replica counters (global) • Injector counters (global) • Server (Global) counters (global)