25.6.16 NDB API 统计计数器和变量
NDB 对象执行或影响的各种统计计数器可用。这些操作包括启动和关闭(或中止)事务;主键和唯一键操作;表、范围和剪枝扫描;线程阻塞,等待各种操作完成;NDBCLUSTER
发送和接收数据和事件。计数器在 NDB 内核中被递增,每当 NDB API 调用被执行或数据被发送到或从数据节点时。 mysqld 将这些计数器暴露为系统状态变量;它们的值可以在 SHOW STATUS
的输出中读取,也可以通过查询性能_schema 中的 session_ status
或 global_status
表。通过比较在操作 NDB 表的语句之前和之后的值,您可以观察对应的 API 级别操作,并且了解执行语句的成本。
您可以使用以下SHOW STATUS
语句列出所有这些状态变量:
mysql> SHOW STATUS LIKE 'ndb_api%';
+----------------------------------------------+-------------+
| Variable_name | Value |
+----------------------------------------------+-------------+
| Ndb_api_wait_exec_complete_count | 11 |
| Ndb_api_wait_scan_result_count | 14 |
| Ndb_api_wait_meta_request_count | 74 |
| Ndb_api_wait_nanos_count | 31453031678 |
| Ndb_api_bytes_sent_count | 3336 |
| Ndb_api_bytes_received_count | 103568 |
| Ndb_api_trans_start_count | 10 |
| Ndb_api_trans_commit_count | 2 |
| Ndb_api_trans_abort_count | 4 |
| Ndb_api_trans_close_count | 10 |
| Ndb_api_pk_op_count | 6 |
| Ndb_api_uk_op_count | 0 |
| Ndb_api_table_scan_count | 3 |
| Ndb_api_range_scan_count | 1 |
| Ndb_api_pruned_scan_count | 0 |
| Ndb_api_scan_batch_count | 3 |
| Ndb_api_read_row_count | 11 |
| Ndb_api_trans_local_read_row_count | 9 |
| Ndb_api_adaptive_send_forced_count | 5 |
| Ndb_api_adaptive_send_unforced_count | 11 |
| Ndb_api_adaptive_send_deferred_count | 0 |
| Ndb_api_event_data_count | 0 |
| Ndb_api_event_nondata_count | 0 |
| Ndb_api_event_bytes_count | 0 |
| Ndb_api_event_data_count_injector | 0 |
| Ndb_api_event_nondata_count_injector | 0 |
| Ndb_api_event_bytes_count_injector | 0 |
| Ndb_api_wait_exec_complete_count_slave | 0 |
| Ndb_api_wait_scan_result_count_slave | 0 |
| Ndb_api_wait_meta_request_count_slave | 0 |
| Ndb_api_wait_nanos_count_slave | 0 |
| Ndb_api_bytes_sent_count_slave | 0 |
| Ndb_api_bytes_received_count_slave | 0 |
| Ndb_api_trans_start_count_slave | 0 |
| Ndb_api_trans_commit_count_slave | 0 |
| Ndb_api_trans_abort_count_slave | 0 |
| Ndb_api_trans_close_count_slave | 0 |
| Ndb_api_pk_op_count_slave | 0 |
| Ndb_api_uk_op_count_slave | 0 |
| Ndb_api_table_scan_count_slave | 0 |
| Ndb_api_range_scan_count_slave | 0 |
| Ndb_api_pruned_scan_count_slave | 0 |
| Ndb_api_scan_batch_count_slave | 0 |
| Ndb_api_read_row_count_slave | 0 |
| Ndb_api_trans_local_read_row_count_slave | 0 |
| Ndb_api_adaptive_send_forced_count_slave | 0 |
| Ndb_api_adaptive_send_unforced_count_slave | 0 |
| Ndb_api_adaptive_send_deferred_count_slave | 0 |
| Ndb_api_wait_exec_complete_count_replica | 0 |
| Ndb_api_wait_scan_result_count_replica | 0 |
| Ndb_api_wait_meta_request_count_replica | 0 |
| Ndb_api_wait_nanos_count_replica | 0 |
| Ndb_api_bytes_sent_count_replica | 0 |
| Ndb_api_bytes_received_count_replica | 0 |
| Ndb_api_trans_start_count_replica | 0 |
| Ndb_api_trans_commit_count_replica | 0 |
| Ndb_api_trans_abort_count_replica | 0 |
| Ndb_api_trans_close_count_replica | 0 |
| Ndb_api_pk_op_count_replica | 0 |
| Ndb_api_uk_op_count_replica | 0 |
| Ndb_api_table_scan_count_replica | 0 |
| Ndb_api_range_scan_count_replica | 0 |
| Ndb_api_pruned_scan_count_replica | 0 |
| Ndb_api_scan_batch_count_replica | 0 |
| Ndb_api_read_row_count_replica | 0 |
| Ndb_api_trans_local_read_row_count_replica | 0 |
| Ndb_api_adaptive_send_forced_count_replica | 0 |
| Ndb_api_adaptive_send_unforced_count_replica | 0 |
| Ndb_api_adaptive_send_deferred_count_replica | 0 |
| Ndb_api_wait_exec_complete_count_session | 0 |
| Ndb_api_wait_scan_result_count_session | 3 |
| Ndb_api_wait_meta_request_count_session | 6 |
| Ndb_api_wait_nanos_count_session | 2022486 |
| Ndb_api_bytes_sent_count_session | 268 |
| Ndb_api_bytes_received_count_session | 10332 |
| Ndb_api_trans_start_count_session | 1 |
| Ndb_api_trans_commit_count_session | 0 |
| Ndb_api_trans_abort_count_session | 0 |
| Ndb_api_trans_close_count_session | 1 |
| Ndb_api_pk_op_count_session | 0 |
| 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 | 2 |
| Ndb_api_read_row_count_session | 2 |
| Ndb_api_trans_local_read_row_count_session | 2 |
| Ndb_api_adaptive_send_forced_count_session | 1 |
| Ndb_api_adaptive_send_unforced_count_session | 0 |
| Ndb_api_adaptive_send_deferred_count_session | 0 |
+----------------------------------------------+-------------+
90 rows in set (0.00 sec)
这些状态变量也可以从性能chema的session_status
和global_status
表中获取,如下所示:
mysql> SELECT * FROM performance_schema.session_status
-> WHERE VARIABLE_NAME LIKE 'ndb_api%';
+----------------------------------------------+----------------+
| VARIABLE_NAME | VARIABLE_VALUE |
+----------------------------------------------+----------------+
| Ndb_api_wait_exec_complete_count | 11 |
| Ndb_api_wait_scan_result_count | 14 |
| Ndb_api_wait_meta_request_count | 81 |
| Ndb_api_wait_nanos_count | 119485762051 |
| Ndb_api_bytes_sent_count | 3476 |
| Ndb_api_bytes_received_count | 105372 |
| Ndb_api_trans_start_count | 10 |
| Ndb_api_trans_commit_count | 2 |
| Ndb_api_trans_abort_count | 4 |
| Ndb_api_trans_close_count | 10 |
| Ndb_api_pk_op_count | 6 |
| Ndb_api_uk_op_count | 0 |
| Ndb_api_table_scan_count | 3 |
| Ndb_api_range_scan_count | 1 |
| Ndb_api_pruned_scan_count | 0 |
| Ndb_api_scan_batch_count | 3 |
| Ndb_api_read_row_count | 11 |
| Ndb_api_trans_local_read_row_count | 9 |
| Ndb_api_adaptive_send_forced_count | 5 |
| Ndb_api_adaptive_send_unforced_count | 11 |
| Ndb_api_adaptive_send_deferred_count | 0 |
| Ndb_api_event_data_count | 0 |
| Ndb_api_event_nondata_count | 0 |
| Ndb_api_event_bytes_count | 0 |
| Ndb_api_event_data_count_injector | 0 |
| Ndb_api_event_nondata_count_injector | 0 |
| Ndb_api_event_bytes_count_injector | 0 |
| Ndb_api_wait_exec_complete_count_slave | 0 |
| Ndb_api_wait_scan_result_count_slave | 0 |
| Ndb_api_wait_meta_request_count_slave | 0 |
| Ndb_api_wait_nanos_count_slave | 0 |
| Ndb_api_bytes_sent_count_slave | 0 |
| Ndb_api_bytes_received_count_slave | 0 |
| Ndb_api_trans_start_count_slave | 0 |
| Ndb_api_trans_commit_count_slave | 0 |
| Ndb_api_trans_abort_count_slave | 0 |
| Ndb_api_trans_close_count_slave | 0 |
| Ndb_api_pk_op_count_slave | 0 |
| Ndb_api_uk_op_count_slave | 0 |
| Ndb_api_table_scan_count_slave | 0 |
| Ndb_api_range_scan_count_slave | 0 |
| Ndb_api_pruned_scan_count_slave | 0 |
| Ndb_api_scan_batch_count_slave | 0 |
| Ndb_api_read_row_count_slave | 0 |
| Ndb_api_trans_local_read_row_count_slave | 0 |
| Ndb_api_adaptive_send_forced_count_slave | 0 |
| Ndb_api_adaptive_send_unforced_count_slave | 0 |
| Ndb_api_adaptive_send_deferred_count_slave | 0 |
| Ndb_api_wait_exec_complete_count_replica | 0 |
| Ndb_api_wait_scan_result_count_replica | 0 |
| Ndb_api_wait_meta_request_count_replica | 0 |
| Ndb_api_wait_nanos_count_replica | 0 |
| Ndb_api_bytes_sent_count_replica | 0 |
| Ndb_api_bytes_received_count_replica | 0 |
| Ndb_api_trans_start_count_replica | 0 |
| Ndb_api_trans_commit_count_replica | 0 |
| Ndb_api_trans_abort_count_replica | 0 |
| Ndb_api_trans_close_count_replica | 0 |
| Ndb_api_pk_op_count_replica | 0 |
| Ndb_api_uk_op_count_replica | 0 |
| Ndb_api_table_scan_count_replica | 0 |
| Ndb_api_range_scan_count_replica | 0 |
| Ndb_api_pruned_scan_count_replica | 0 |
| Ndb_api_scan_batch_count_replica | 0 |
| Ndb_api_read_row_count_replica | 0 |
| Ndb_api_trans_local_read_row_count_replica | 0 |
| Ndb_api_adaptive_send_forced_count_replica | 0 |
| Ndb_api_adaptive_send_unforced_count_replica | 0 |
| Ndb_api_adaptive_send_deferred_count_replica | 0 |
| Ndb_api_wait_exec_complete_count_session | 0 |
| Ndb_api_wait_scan_result_count_session | 3 |
| Ndb_api_wait_meta_request_count_session | 6 |
| Ndb_api_wait_nanos_count_session | 2022486 |
| Ndb_api_bytes_sent_count_session | 268 |
| Ndb_api_bytes_received_count_session | 10332 |
| Ndb_api_trans_start_count_session | 1 |
| Ndb_api_trans_commit_count_session | 0 |
| Ndb_api_trans_abort_count_session | 0 |
| Ndb_api_trans_close_count_session | 1 |
| Ndb_api_pk_op_count_session | 0 |
| 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 | 2 |
| Ndb_api_read_row_count_session | 2 |
| Ndb_api_trans_local_read_row_count_session | 2 |
| Ndb_api_adaptive_send_forced_count_session | 1 |
| Ndb_api_adaptive_send_unforced_count_session | 0 |
| Ndb_api_adaptive_send_deferred_count_session | 0 |
+----------------------------------------------+----------------+
90 rows in set (0.00 sec)
mysql> SELECT * FROM performance_schema.global_status
-> WHERE VARIABLE_NAME LIKE 'ndb_api%';
+----------------------------------------------+----------------+
| VARIABLE_NAME | VARIABLE_VALUE |
+----------------------------------------------+----------------+
| Ndb_api_wait_exec_complete_count | 11 |
| Ndb_api_wait_scan_result_count | 14 |
| Ndb_api_wait_meta_request_count | 88 |
| Ndb_api_wait_nanos_count | 159810484729 |
| Ndb_api_bytes_sent_count | 3616 |
| Ndb_api_bytes_received_count | 107176 |
| Ndb_api_trans_start_count | 10 |
| Ndb_api_trans_commit_count | 2 |
| Ndb_api_trans_abort_count | 4 |
| Ndb_api_trans_close_count | 10 |
| Ndb_api_pk_op_count | 6 |
| Ndb_api_uk_op_count | 0 |
| Ndb_api_table_scan_count | 3 |
| Ndb_api_range_scan_count | 1 |
| Ndb_api_pruned_scan_count | 0 |
| Ndb_api_scan_batch_count | 3 |
| Ndb_api_read_row_count | 11 |
| Ndb_api_trans_local_read_row_count | 9 |
| Ndb_api_adaptive_send_forced_count | 5 |
| Ndb_api_adaptive_send_unforced_count | 11 |
| Ndb_api_adaptive_send_deferred_count | 0 |
| Ndb_api_event_data_count | 0 |
| Ndb_api_event_nondata_count | 0 |
| Ndb_api_event_bytes_count | 0 |
| Ndb_api_event_data_count_injector | 0 |
| Ndb_api_event_nondata_count_injector | 0 |
| Ndb_api_event_bytes_count_injector | 0 |
| Ndb_api_wait_exec_complete_count_slave | 0 |
| Ndb_api_wait_scan_result_count_slave | 0 |
| Ndb_api_wait_meta_request_count_slave | 0 |
| Ndb_api_wait_nanos_count_slave | 0 |
| Ndb_api_bytes_sent_count_slave | 0 |
| Ndb_api_bytes_received_count_slave | 0 |
| Ndb_api_trans_start_count_slave | 0 |
| Ndb_api_trans_commit_count_slave | 0 |
| Ndb_api_trans_abort_count_slave | 0 |
| Ndb_api_trans_close_count_slave | 0 |
| Ndb_api_pk_op_count_slave | 0 |
| Ndb_api_uk_op_count_slave | 0 |
| Ndb_api_table_scan_count_slave | 0 |
| Ndb_api_range_scan_count_slave | 0 |
| Ndb_api_pruned_scan_count_slave | 0 |
| Ndb_api_scan_batch_count_slave | 0 |
| Ndb_api_read_row_count_slave | 0 |
| Ndb_api_trans_local_read_row_count_slave | 0 |
| Ndb_api_adaptive_send_forced_count_slave | 0 |
| Ndb_api_adaptive_send_unforced_count_slave | 0 |
| Ndb_api_adaptive_send_deferred_count_slave | 0 |
| Ndb_api_wait_exec_complete_count_replica | 0 |
| Ndb_api_wait_scan_result_count_replica | 0 |
| Ndb_api_wait_meta_request_count_replica | 0 |
| Ndb_api_wait_nanos_count_replica | 0 |
| Ndb_api_bytes_sent_count_replica | 0 |
| Ndb_api_bytes_received_count_replica | 0 |
| Ndb_api_trans_start_count_replica | 0 |
| Ndb_api_trans_commit_count_replica | 0 |
| Ndb_api_trans_abort_count_replica | 0 |
| Ndb_api_trans_close_count_replica | 0 |
| Ndb_api_pk_op_count_replica | 0 |
| Ndb_api_uk_op_count_replica | 0 |
| Ndb_api_table_scan_count_replica | 0 |
| Ndb_api_range_scan_count_replica | 0 |
| Ndb_api_pruned_scan_count_replica | 0 |
| Ndb_api_scan_batch_count_replica | 0 |
| Ndb_api_read_row_count_replica | 0 |
| Ndb_api_trans_local_read_row_count_replica | 0 |
| Ndb_api_adaptive_send_forced_count_replica | 0 |
| Ndb_api_adaptive_send_unforced_count_replica | 0 |
| Ndb_api_adaptive_send_deferred_count_replica | 0 |
| Ndb_api_wait_exec_complete_count_session | 0 |
| Ndb_api_wait_scan_result_count_session | 3 |
| Ndb_api_wait_meta_request_count_session | 6 |
| Ndb_api_wait_nanos_count_session | 2022486 |
| Ndb_api_bytes_sent_count_session | 268 |
| Ndb_api_bytes_received_count_session | 10332 |
| Ndb_api_trans_start_count_session | 1 |
| Ndb_api_trans_commit_count_session | 0 |
| Ndb_api_trans_abort_count_session | 0 |
| Ndb_api_trans_close_count_session | 1 |
| Ndb_api_pk_op_count_session | 0 |
| 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 | 2 |
| Ndb_api_read_row_count_session | 2 |
| Ndb_api_trans_local_read_row_count_session | 2 |
| Ndb_api_adaptive_send_forced_count_session | 1 |
| Ndb_api_adaptive_send_unforced_count_session | 0 |
| Ndb_api_adaptive_send_deferred_count_session | 0 |
+----------------------------------------------+----------------+
90 rows in set (0.01 sec)
每个Ndb
对象都有自己的计数器。NDB API应用程序可以读取计数器的值,以用于优化或监控。对于使用多个Ndb
对象的多线程客户端,可以获取所有属于给定Ndb_cluster_connection
的Ndb
对象的累积视图。
四组这些计数器是公开的。其中一组只应用于当前会话;另外三组是全局的。这与它们的值可以作为 either 会话或全局状态变量在mysql 客户端中不同。这意味着,在使用SHOW STATUS
时,指定SESSION
或GLOBAL
关键字没有影响NDB API统计状态变量的值,每个变量的值都是一样的,无论是从session_status
或global_status
表中获取。
-
会话计数器(session specific)
会话计数器与
Ndb
对象在当前会话中使用的相关。其他 MySQL 客户端使用这些对象不影响这些计数器。为了避免与标准 MySQL 会话变量混淆,我们将对应于这些 NDB API 会话计数器的变量称为“
_session
变量”,带有前导下划线。 -
副本计数器(global)
这个计数器集与
Ndb
对象相关,如果replica SQL线程存在。如果mysqld不作为replica或不使用NDB
表,则所有这些计数器都为0。我们将相关的状态变量称为“
_replica
变量”(带有前导下划线)。 -
Injector计数器(全局)
Injector计数器与
Ndb
对象相关,用于监听集群事件的二进制日志注入线程,即使不写入二进制日志,mysqld仍然继续监听某些事件,如架构变化。我们将NDB API Injector计数器对应的状态变量称为“
_injector
变量”(带有前导下划线)。 -
服务器(全局)计数器(全局)
这个计数器集与当前使用的
Ndb
对象相关,这包括所有MySQL客户端应用程序、副本SQL线程(如果存在)、二进制日志注入器和NDB
utility线程。我们将与这些计数器对应的状态变量称为“全局变量”或“mysqld级别变量”。
您可以通过在变量名称中添加子字符串session
、replica
或injector
来获取特定变量的值(加上公共前缀Ndb_api
)。对于_session变量,这可以按照以下方式进行:
mysql> SHOW STATUS LIKE 'ndb_api%session';
+----------------------------------------------+---------+
| Variable_name | Value |
+----------------------------------------------+---------+
| Ndb_api_wait_exec_complete_count_session | 0 |
| Ndb_api_wait_scan_result_count_session | 3 |
| Ndb_api_wait_meta_request_count_session | 6 |
| Ndb_api_wait_nanos_count_session | 2022486 |
| Ndb_api_bytes_sent_count_session | 268 |
| Ndb_api_bytes_received_count_session | 10332 |
| Ndb_api_trans_start_count_session | 1 |
| Ndb_api_trans_commit_count_session | 0 |
| Ndb_api_trans_abort_count_session | 0 |
| Ndb_api_trans_close_count_session | 1 |
| Ndb_api_pk_op_count_session | 0 |
| 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 | 2 |
| Ndb_api_read_row_count_session | 2 |
| Ndb_api_trans_local_read_row_count_session | 2 |
| Ndb_api_adaptive_send_forced_count_session | 1 |
| Ndb_api_adaptive_send_unforced_count_session | 0 |
| Ndb_api_adaptive_send_deferred_count_session | 0 |
+----------------------------------------------+---------+
21 rows in set (0.00 sec)
要获得NDB APImysqld-级别状态变量的列表,请将变量名称过滤为以ndb_api
开头并以_count
结尾,如下所示:
mysql> SELECT * FROM performance_schema.session_status
-> WHERE VARIABLE_NAME LIKE 'ndb_api%count';
+------------------------------------+----------------+
| VARIABLE_NAME | VARIABLE_VALUE |
+------------------------------------+----------------+
| NDB_API_WAIT_EXEC_COMPLETE_COUNT | 4 |
| NDB_API_WAIT_SCAN_RESULT_COUNT | 3 |
| NDB_API_WAIT_META_REQUEST_COUNT | 28 |
| NDB_API_WAIT_NANOS_COUNT | 53756398 |
| NDB_API_BYTES_SENT_COUNT | 1060 |
| NDB_API_BYTES_RECEIVED_COUNT | 9724 |
| NDB_API_TRANS_START_COUNT | 3 |
| NDB_API_TRANS_COMMIT_COUNT | 2 |
| NDB_API_TRANS_ABORT_COUNT | 0 |
| NDB_API_TRANS_CLOSE_COUNT | 3 |
| NDB_API_PK_OP_COUNT | 2 |
| 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 |
+------------------------------------+----------------+
21 rows in set (0.09 sec)
不所有计数器都反映在所有4个状态变量中。对于事件计数器DataEventsRecvdCount
、NondataEventsRecvdCount
和EventBytesRecvdCount
,只有_injector
和mysqld-级NDB API状态变量可用:
mysql> SHOW STATUS LIKE 'ndb_api%event%';
+--------------------------------------+-------+
| Variable_name | Value |
+--------------------------------------+-------+
| Ndb_api_event_data_count_injector | 0 |
| Ndb_api_event_nondata_count_injector | 0 |
| Ndb_api_event_bytes_count_injector | 0 |
| Ndb_api_event_data_count | 0 |
| Ndb_api_event_nondata_count | 0 |
| Ndb_api_event_bytes_count | 0 |
+--------------------------------------+-------+
6 rows in set (0.00 sec)
_injector
状态变量对任何其他NDB API计数器都没有实现,如下所示:
mysql> SHOW STATUS LIKE 'ndb_api%injector%';
+--------------------------------------+-------+
| Variable_name | Value |
+--------------------------------------+-------+
| Ndb_api_event_data_count_injector | 0 |
| Ndb_api_event_nondata_count_injector | 0 |
| Ndb_api_event_bytes_count_injector | 0 |
+--------------------------------------+-------+
3 rows in set (0.00 sec)
状态变量的名称可以轻松地与相应计数器的名称相关联。每个NDB API统计计数器在以下表格中列出,包括描述,以及对应于该计数器的MySQL服务器状态变量名称。
表25.39 NDB API统计计数器
Counter Name | Description | Status Variables (by statistic type):
|
---|---|---|
WaitExecCompleteCount |
线程等待操作完成而被阻塞的次数。包括所有execute() 调用,以及隐式执行的blob操作和自动递增不对客户端可见。 |
|
WaitScanResultCount |
Number of times thread has been blocked while waiting for a scan-based signal, such waiting for additional results, or for a scan to close. | |
WaitMetaRequestCount |
Number of times thread has been blocked waiting for a metadata-based signal; this can occur when waiting for a DDL operation or for an epoch to be started (or ended). | |
WaitNanosCount |
Total time (in nanoseconds) spent waiting for some type of signal from the data nodes. | |
BytesSentCount |
Amount of data (in bytes) sent to the data nodes | |
BytesRecvdCount |
Amount of data (in bytes) received from the data nodes | |
TransStartCount |
Number of transactions started. | |
TransCommitCount |
Number of transactions committed. | |
TransAbortCount |
Number of transactions aborted. | |
TransCloseCount |
Number of transactions aborted. (This value may be greater than the sum of TransCommitCount and TransAbortCount .) |
|
PkOpCount |
Number of operations based on or using primary keys. This count includes blob-part table operations, implicit unlocking operations, and auto-increment operations, as well as primary key operations normally visible to MySQL clients. | |
UkOpCount |
Number of operations based on or using unique keys. | |
TableScanCount |
Number of table scans that have been started. This includes scans of internal tables. | |
RangeScanCount |
Number of range scans that have been started. | |
PrunedScanCount |
Number of scans that have been pruned to a single partition. | |
ScanBatchCount |
Number of batches of rows received. (A batch in this context is a set of scan results from a single fragment.) | |
ReadRowCount |
Total number of rows that have been read. Includes rows read using primary key, unique key, and scan operations. | |
TransLocalReadRowCount |
Number of rows read from the data same node on which the transaction was being run. | |
DataEventsRecvdCount |
Number of row change events received. |
|
NondataEventsRecvdCount |
Number of events received, other than row change events. | |
EventBytesRecvdCount |
Number of bytes of events received. |
要查看所有已提交事务的计数—that is, all TransCommitCount
计数器状态变量—you can filter the results of SHOW STATUS
for the substring trans_commit_count
, like this:
mysql> SHOW STATUS LIKE '%trans_commit_count%';
+------------------------------------+-------+
| Variable_name | Value |
+------------------------------------+-------+
| Ndb_api_trans_commit_count_session | 1 |
| Ndb_api_trans_commit_count_slave | 0 |
| Ndb_api_trans_commit_count | 2 |
+------------------------------------+-------+
3 rows in set (0.00 sec)
从这里可以确定,在当前mysql 客户端会话中已经提交了1个事务,而在这个mysqld 中自从最后重启以来已经提交了2个事务。
您可以通过比较相应的_session
状态变量的值来了解各种NDB API计数器是如何被给定的SQL语句增量的。例如,在这个示例中,我们首先从SHOW STATUS
获取初始值,然后在 test
数据库中创建一个名为t
的NDB
表,该表只有一个列:
mysql> SHOW STATUS LIKE 'ndb_api%session%';
+--------------------------------------------+--------+
| Variable_name | Value |
+--------------------------------------------+--------+
| Ndb_api_wait_exec_complete_count_session | 2 |
| Ndb_api_wait_scan_result_count_session | 0 |
| Ndb_api_wait_meta_request_count_session | 3 |
| Ndb_api_wait_nanos_count_session | 820705 |
| Ndb_api_bytes_sent_count_session | 132 |
| Ndb_api_bytes_received_count_session | 372 |
| Ndb_api_trans_start_count_session | 1 |
| Ndb_api_trans_commit_count_session | 1 |
| Ndb_api_trans_abort_count_session | 0 |
| Ndb_api_trans_close_count_session | 1 |
| Ndb_api_pk_op_count_session | 1 |
| 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 | 1 |
| Ndb_api_trans_local_read_row_count_session | 1 |
+--------------------------------------------+--------+
18 rows in set (0.00 sec)
mysql> USE test;
Database changed
mysql> CREATE TABLE t (c INT) ENGINE NDBCLUSTER;
Query OK, 0 rows affected (0.85 sec)
现在,您可以执行一个新的SHOW STATUS
语句,并观察变化,如下所示(输出中高亮显示的行):
mysql> SHOW STATUS LIKE 'ndb_api%session%';
+--------------------------------------------+-----------+
| Variable_name | Value |
+--------------------------------------------+-----------+
| Ndb_api_wait_exec_complete_count_session | 8 |
| Ndb_api_wait_scan_result_count_session | 0 |
| Ndb_api_wait_meta_request_count_session | 17 |
| Ndb_api_wait_nanos_count_session | 706871709 |
| Ndb_api_bytes_sent_count_session | 2376 |
| Ndb_api_bytes_received_count_session | 3844 |
| Ndb_api_trans_start_count_session | 4 |
| Ndb_api_trans_commit_count_session | 4 |
| Ndb_api_trans_abort_count_session | 0 |
| Ndb_api_trans_close_count_session | 4 |
| Ndb_api_pk_op_count_session | 6 |
| 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)
类似地,您可以看到插入SHOW STATUS
语句中NDB API统计计数器的变化:插入行,然后运行同样的SHOW STATUS
语句,如下所示:
mysql> INSERT INTO t VALUES (100);
Query OK, 1 row affected (0.00 sec)
mysql> SHOW STATUS LIKE 'ndb_api%session%';
+--------------------------------------------+-----------+
| 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)
我们可以从这些结果中做出以下观察:
-
虽然我们没有明确地为t指定主键,但是在创建该表时执行了5个主键操作(Ndb_api_pk_op_count_session的“before”和“after”值之间的差异,或者6减1)。这反映了使用NDB存储引擎的所有表都具有隐藏主键的特性。
-
通过比较Ndb_api_wait_nanos_count_session的连续值,我们可以看到NDB API操作,实现CREATE TABLE语句等待了数据节点的响应时间远长(706871709 - 820705 = 706051004纳秒,约0.7秒)than those executed by theINSERT(707370418 - 706871709 = 498709 ns or roughly .0005 second)。这些语句在mysql客户端报告的执行时间与这些数字相近。
在没有足够(nanosecond)时间分辨率的平台上,小变化可能不会总是可见于
Ndb_api_wait_nanos_count_session
、Ndb_api_wait_nanos_count_replica
或Ndb_api_wait_nanos_count
的值中,因为SQL语句执行非常快。 -
INSERT
语句同时增加了Ndb_api_read_row_count_session
和Ndb_api_trans_local_read_row_count_session
NDB API统计计数器的值,反映在Ndb_api_read_row_count_session
和Ndb_api_trans_local_read_row_count_session
的增加值中。