NDB API Statistics Counters and Variables | Ndb_api_uk_op_count_session | 0 | | Ndb_api_table_scan_count_session | 0 | | Ndb_api_range_scan_count_session | 0 | | Ndb_api_pruned_scan_count_session | 0 | | Ndb_api_scan_batch_count_session | 0 | | Ndb_api_read_row_count_session | 2 | | Ndb_api_trans_local_read_row_count_session | 1 | +--------------------------------------------+-----------+ 18 rows in set (0.00 sec) mysql>  INSERT INTO t VALUES (100); Query OK, 1 row affected (0.00 sec) mysql>  SHOW STATUS LIKE ’ndb_api%session%’; Similarly, you can see the changes in the NDB API statistics counters caused by inserting a row into  t : Insert the row, then run the same  SHOW STATUS  statement used in the previous example, as shown here: +--------------------------------------------+-----------+ | Variable_name | Value | +--------------------------------------------+-----------+ | Ndb_api_wait_exec_complete_count_session | 11 | | Ndb_api_wait_scan_result_count_session | 6 | | Ndb_api_wait_meta_request_count_session | 20 | | Ndb_api_wait_nanos_count_session | 707370418 | | Ndb_api_bytes_sent_count_session | 2724 | | Ndb_api_bytes_received_count_session | 4116 | | Ndb_api_trans_start_count_session | 7 | | Ndb_api_trans_commit_count_session | 6 | | Ndb_api_trans_abort_count_session | 0 | | Ndb_api_trans_close_count_session | 7 | | Ndb_api_pk_op_count_session | 8 | | Ndb_api_uk_op_count_session | 0 | | Ndb_api_table_scan_count_session | 1 | | Ndb_api_range_scan_count_session | 0 | | Ndb_api_pruned_scan_count_session | 0 | | Ndb_api_scan_batch_count_session | 0 | | Ndb_api_read_row_count_session | 3 | | Ndb_api_trans_local_read_row_count_session | 2 | +--------------------------------------------+-----------+ 18 rows in set (0.00 sec) We can make a number of observations from these results: •Although we created  t  with no explicit primary key, 5 primary key operations were performed in doing so (the difference in the “before”  and “after”  values of  Ndb_api_pk_op_count_session , or 6 minus 1). This reflects the creation of the hidden primary key that is a feature of all tables using the  NDB  storage engine. •By comparing successive values for  Ndb_api_wait_nanos_count_session , we can see that the NDB API operations implementing the  CREATE TABLE  statement waited much longer (706871709 - 820705 = 706051004 nanoseconds, or approximately 0.7 second) for responses from the data nodes than those executed by the  INSERT  (707370418 - 706871709 = 498709 ns or roughly .0005 second). The execution times reported for these statements in the  mysql  client correlate roughly with these figures. •The  INSERT  statement incremented both the  ReadRowCount  and  TransLocalReadRowCount  NDB API statistics counters, as reflected by the increased values of  Ndb_api_read_row_count_session and  Ndb_api_trans_local_read_row_count_session . On platforms without sufficient (nanosecond) time resolution, small changes in the value of the  WaitNanosCount  NDB API counter due to SQL statements that execute very quickly may not always be visible in the values of  Ndb_api_wait_nanos_count_session , Ndb_api_wait_nanos_count_slave , or  Ndb_api_wait_nanos_count . 4519