MySQL 9.0 版本注意事項
許多類型的統計計數器與 Ndb 物件執行或影響的動作相關。這類動作包括啟動和關閉 (或中止) 交易；主索引鍵和唯一索引鍵操作；資料表、範圍和修剪掃描；執行緒在等待各種操作完成時被封鎖；以及 NDBCLUSTER 傳送和接收的資料和事件。每當進行 NDB API 呼叫或將資料傳送至資料節點或由資料節點接收時，計數器會在 NDB 核心內遞增。mysqld 會將這些計數器公開為系統狀態變數；其值可以在 SHOW STATUS 的輸出中讀取，或藉由查詢效能架構 session_status 或 global_status 資料表來讀取。藉由比較在 NDB 資料表上操作的陳述式之前和之後的值，您可以觀察在 API 層級採取的對應動作，以及執行陳述式的成本。
您可以使用下列 SHOW STATUS 陳述式列出所有這些狀態變數
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)這些狀態變數也可從效能架構 session_status 和 global_status 資料表取得，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)每個 Ndb 物件都有自己的計數器。NDB API 應用程式可以讀取計數器的值，以用於最佳化或監控。對於同時使用多個 Ndb 物件的多執行緒用戶端，也可以從屬於給定 Ndb_cluster_connection 的所有 Ndb 物件取得計數器的總和檢視。
公開了四組這些計數器。一組僅適用於目前的階段作業；另外 3 組是全域的。 儘管它們的值可以作為 mysql 用戶端中的階段作業或全域狀態變數取得。這表示指定 SHOW STATUS 的 SESSION 或 GLOBAL 關鍵字對 NDB API 統計狀態變數報告的值沒有影響，並且無論該值是從 session_status 或 global_status 資料表的對等欄取得，每個這些變數的值都相同。
階段作業計數器 (階段作業特定)
階段作業計數器與目前階段作業 (僅) 使用的
Ndb物件相關。其他 MySQL 用戶端對此類物件的使用不會影響這些計數。為了盡量減少與標準 MySQL 階段作業變數的混淆，我們將對應於這些 NDB API 階段作業計數器的變數稱為 「
_session變數」，並帶有前導底線。複本計數器 (全域)
這組計數器與複本 SQL 執行緒 (如果有的話) 使用的
Ndb物件相關。如果此 mysqld 不作為複本，或不使用NDB資料表，則所有這些計數均為 0。我們將相關的狀態變數稱為 「
_replica變數」 (帶有前導底線)。注入器計數器 (全域)
注入器計數器與二進位日誌注入器執行緒用來接聽叢集事件的
Ndb物件相關。即使在不寫入二進位日誌時，附加到 NDB Cluster 的 mysqld 處理程序仍會繼續接聽某些事件，例如架構變更。我們將對應於 NDB API 注入器計數器的狀態變數稱為 「
_injector變數」 (帶有前導底線)。伺服器 (全域) 計數器 (全域)
這組計數器與此 mysqld 目前使用的所有
Ndb物件相關。這包括所有 MySQL 用戶端應用程式、複本 SQL 執行緒 (如果有的話)、二進位日誌注入器和NDB公用程式執行緒。我們將對應於這些計數器的狀態變數稱為 「全域變數」或 「mysqld 層級變數」。
您可以藉由額外篩選變數名稱中的子字串 session、replica 或 injector (以及通用前置詞 Ndb_api) 來取得特定的一組變數的值。對於 _session 變數，可以如下所示進行此作業
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)若要取得 NDB API mysqld 層級狀態變數的清單，請篩選以 ndb_api 開頭並以 _count 結尾的變數名稱，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)並非所有計數器都會反映在所有 4 組狀態變數中。對於事件計數器 DataEventsRecvdCount、NondataEventsRecvdCount 和 EventBytesRecvdCount，僅有 _injector 和 mysqld 層級 NDB API 狀態變數可用
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)
對於任何其他 NDB API 計數器，未實作 _injector 狀態變數，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)狀態變數的名稱可以很容易地與對應計數器的名稱相關聯。下表中列出了每個 NDB API 統計計數器，並提供說明以及對應於此計數器的任何 MySQL 伺服器狀態變數的名稱。
表 25.39 NDB API 統計計數器
| 計數器名稱 | 描述 | 狀態變數 (依統計類型)
|
|---|---|---|
WaitExecCompleteCount |
執行緒在等待操作完成執行時被封鎖的次數。包括所有 execute() 呼叫以及對用戶端不可見的 blob 操作和自動遞增的隱含執行。 |
|
WaitScanResultCount |
執行緒在等待以掃描為基礎的信號時被封鎖的次數，例如等待其他結果，或等待掃描關閉。 | |
WaitMetaRequestCount |
執行緒在等待以中繼資料為基礎的信號時被封鎖的次數；這可能會在等待 DDL 操作或等待啟動 (或結束) epoch 時發生。 | |
WaitNanosCount |
等待來自資料節點的某種信號所花費的總時間 (以奈秒為單位)。 | |
BytesSentCount |
傳送至資料節點的資料量 (以位元組為單位) | |
BytesRecvdCount |
從資料節點接收的資料量 (以位元組為單位) | |
TransStartCount |
啟動的交易數量。 | |
TransCommitCount |
已提交的交易數量。 | |
TransAbortCount |
已中止的交易數量。 | |
TransCloseCount |
已中止的交易數量。(此值可能大於 TransCommitCount 和 TransAbortCount 的總和。) |
|
PkOpCount |
基於或使用主鍵的操作數量。此計數包括 blob 部分表格操作、隱式解鎖操作和自動遞增操作，以及通常對 MySQL 客戶端可見的主鍵操作。 | |
UkOpCount |
基於或使用唯一鍵的操作數量。 | |
TableScanCount |
已啟動的表格掃描數量。這包括內部表格的掃描。 | |
RangeScanCount |
已啟動的範圍掃描數量。 | |
PrunedScanCount |
已修剪到單個分割區的掃描數量。 | |
ScanBatchCount |
接收的行批次數量。(在此上下文中，批次是指來自單個片段的一組掃描結果。) | |
ReadRowCount |
已讀取的行總數。包括使用主鍵、唯一鍵和掃描操作讀取的行。 | |
TransLocalReadRowCount |
從執行交易的同一節點讀取的行數。 | |
DataEventsRecvdCount |
接收到的行變更事件數量。 | |
NondataEventsRecvdCount |
接收到的事件數量，行變更事件除外。 | |
EventBytesRecvdCount |
接收到的事件位元組數。 |
要查看所有已提交交易的計數 (即所有 TransCommitCount 計數器狀態變數)，您可以篩選 SHOW STATUS 的結果，以查找子字串 trans_commit_count，如下所示
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)從這裡您可以確定目前 mysql 用戶端工作階段中已提交 1 個交易，並且自上次重新啟動以來，此 mysqld 上已提交 2 個交易。
您可以透過比較執行陳述式前後對應的 _session 狀態變數值，查看給定 SQL 陳述式如何遞增各種 NDB API 計數器。在本範例中，從 SHOW STATUS 取得初始值後，我們在 test 資料庫中建立一個名為 t 的 NDB 表格，其中包含單一資料欄
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)現在您可以執行新的 SHOW STATUS 陳述式，並觀察變更，如下所示 (變更的行會在輸出中反白顯示)
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)同樣地，您可以查看將列插入 t 所造成的 NDB API 統計計數器變更：插入該列，然後執行與先前範例中使用的相同的 SHOW STATUS 陳述式，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)我們可以從這些結果中得出許多觀察結果
雖然我們建立
t時沒有明確的主鍵，但這樣做時已執行了 5 次主鍵操作 (Ndb_api_pk_op_count_session的 「之前」 和 「之後」 值之差，或 6 減 1)。這反映了所有使用NDB儲存引擎的表格的一項功能，即隱藏的主鍵的建立。透過比較
Ndb_api_wait_nanos_count_session的連續值，我們可以發現，實作CREATE TABLE陳述式的 NDB API 操作等待來自資料節點的回應時間，比INSERT所執行的時間長得多 (706871709 - 820705 = 706051004 奈秒，或大約 0.7 秒) (707370418 - 706871709 = 498709 奈秒，或大約 0.0005 秒)。mysql 用戶端中回報的這些陳述式執行時間大約與這些數字相關。在時間解析度不足 (奈秒) 的平台上，由於執行速度非常快的 SQL 陳述式而導致
WaitNanosCountNDB API 計數器值的小變更，可能不總是能在Ndb_api_wait_nanos_count_session、Ndb_api_wait_nanos_count_replica或Ndb_api_wait_nanos_count的值中看到。INSERT陳述式會遞增ReadRowCount和TransLocalReadRowCountNDB API 統計計數器，這會反映在Ndb_api_read_row_count_session和Ndb_api_trans_local_read_row_count_session的值增加中。