MySQL 9.0 版本說明
本節討論幾個 SQL 語法，這些語法在管理和監控連接到 NDB 叢集的 MySQL 伺服器時，以及在某些情況下提供關於叢集本身的資訊時，可能會很有用。
SHOW ENGINE NDB STATUS,SHOW ENGINE NDBCLUSTER STATUS此語法的輸出包含關於伺服器與叢集連接、NDB 叢集物件的建立和使用，以及 NDB 叢集複製的二進位日誌記錄的資訊。
請參閱第 15.7.7.16 節，「SHOW ENGINE 語法」，以取得使用範例和更詳細的資訊。
可以使用此語法來判斷 MySQL 伺服器中是否啟用叢集支援，如果啟用，則判斷它是否處於活動狀態。
請參閱第 15.7.7.17 節，「SHOW ENGINES 語法」，以取得更詳細的資訊。
SELECT * FROM INFORMATION_SCHEMA.ENGINES [WHERE ENGINE LIKE 'NDB%']這等同於
SHOW ENGINES，但使用INFORMATION_SCHEMA資料庫的ENGINES資料表。與SHOW ENGINES語法的情況不同，可以使用LIKE子句篩選結果，並選擇特定欄以取得可能在指令碼中使用的資訊。例如，下列查詢顯示伺服器是否使用NDB支援建置，如果是，則顯示是否啟用mysql> SELECT ENGINE, SUPPORT FROM INFORMATION_SCHEMA.ENGINES -> WHERE ENGINE LIKE 'NDB%'; +------------+---------+ | ENGINE | SUPPORT | +------------+---------+ | ndbcluster | YES | | ndbinfo | YES | +------------+---------+如果未啟用
NDB支援，則前面的查詢會傳回空集合。請參閱第 28.3.13 節，「INFORMATION_SCHEMA ENGINES 資料表」，以取得更多資訊。此語法提供與
NDB儲存引擎相關的大部分伺服器系統變數及其值的清單，如下所示mysql> SHOW VARIABLES LIKE 'NDB%'; +--------------------------------------------+----------------------------------+ | Variable_name | Value | +--------------------------------------------+----------------------------------+ | ndb_allow_copying_alter_table | ON | | ndb_applier_allow_skip_epoch | OFF | | ndb_applier_conflict_role | NONE | | ndb_autoincrement_prefetch_sz | 512 | | ndb_batch_size | 32768 | | ndb_blob_read_batch_bytes | 65536 | | ndb_blob_write_batch_bytes | 65536 | | ndb_clear_apply_status | ON | | ndb_cluster_connection_pool | 1 | | ndb_cluster_connection_pool_nodeids | | | ndb_connectstring | 127.0.0.1 | | ndb_data_node_neighbour | 0 | | ndb_default_column_format | FIXED | | ndb_deferred_constraints | 0 | | ndb_distribution | KEYHASH | | ndb_eventbuffer_free_percent | 20 | | ndb_eventbuffer_max_alloc | 0 | | ndb_extra_logging | 1 | | ndb_force_send | ON | | ndb_fully_replicated | OFF | | ndb_index_stat_enable | ON | | ndb_index_stat_option | loop_enable=1000ms, loop_idle=1000ms,loop_busy=100ms,update_batch=1,read_batch=4,idle_batch=32, check_batch=8,check_delay=10m,delete_batch=8,clean_delay=1m,error_batch=4, error_delay=1m,evict_batch=8,evict_delay=1m,cache_limit=32M,cache_lowpct=90, zero_total=0 | | ndb_join_pushdown | ON | | ndb_log_apply_status | OFF | | ndb_log_bin | OFF | | ndb_log_binlog_index | ON | | ndb_log_empty_epochs | OFF | | ndb_log_empty_update | OFF | | ndb_log_exclusive_reads | OFF | | ndb_log_fail_terminate | OFF | | ndb_log_orig | OFF | | ndb_log_transaction_compression | OFF | | ndb_log_transaction_compression_level_zstd | 3 | | ndb_log_transaction_dependency | OFF | | ndb_log_transaction_id | OFF | | ndb_log_update_as_write | ON | | ndb_log_update_minimal | OFF | | ndb_log_updated_only | ON | | ndb_metadata_check | ON | | ndb_metadata_check_interval | 60 | | ndb_metadata_sync | OFF | | ndb_mgm_tls | relaxed | | ndb_mgmd_host | 127.0.0.1 | | ndb_nodeid | 0 | | ndb_optimization_delay | 10 | | ndb_optimized_node_selection | 3 | | ndb_read_backup | ON | | ndb_recv_thread_activation_threshold | 8 | | ndb_recv_thread_cpu_mask | | | ndb_replica_batch_size | 2097152 | | ndb_replica_blob_write_batch_bytes | 2097152 | | ndb_report_thresh_binlog_epoch_slip | 10 | | ndb_report_thresh_binlog_mem_usage | 10 | | ndb_row_checksum | 1 | | ndb_schema_dist_lock_wait_timeout | 30 | | ndb_schema_dist_timeout | 120 | | ndb_schema_dist_upgrade_allowed | ON | | ndb_show_foreign_key_mock_tables | OFF | | ndb_slave_conflict_role | NONE | | ndb_table_no_logging | OFF | | ndb_table_temporary | OFF | | ndb_tls_search_path | $HOME/ndb-tls | | ndb_use_copying_alter_table | OFF | | ndb_use_exact_count | OFF | | ndb_use_transactions | ON | | ndb_version | 524544 | | ndb_version_string | ndb-8.4.0 | | ndb_wait_connected | 120 | | ndb_wait_setup | 120 | | ndbinfo_database | ndbinfo | | ndbinfo_max_bytes | 0 | | ndbinfo_max_rows | 10 | | ndbinfo_offline | OFF | | ndbinfo_show_hidden | OFF | | ndbinfo_table_prefix | ndb$ | | ndbinfo_version | 524544 | +--------------------------------------------+----------------------------------+ 74 rows in set (0.01 sec)請參閱第 7.1.8 節，「伺服器系統變數」，以取得更多資訊。
SELECT * FROM performance_schema.global_variables WHERE VARIABLE_NAME LIKE 'NDB%'此語法與前一項所述的
SHOW VARIABLES語法等效，並提供幾乎相同的輸出，如下所示mysql> SELECT * FROM performance_schema.global_variables -> WHERE VARIABLE_NAME LIKE 'NDB%'; +--------------------------------------+---------------------------------------+ | VARIABLE_NAME | VARIABLE_VALUE | +--------------------------------------+---------------------------------------+ | ndb_allow_copying_alter_table | ON | | ndb_autoincrement_prefetch_sz | 512 | | ndb_batch_size | 32768 | | ndb_blob_read_batch_bytes | 65536 | | ndb_blob_write_batch_bytes | 65536 | | ndb_clear_apply_status | ON | | ndb_cluster_connection_pool | 1 | | ndb_cluster_connection_pool_nodeids | | | ndb_connectstring | 127.0.0.1 | | ndb_data_node_neighbour | 0 | | ndb_default_column_format | FIXED | | ndb_deferred_constraints | 0 | | ndb_distribution | KEYHASH | | ndb_eventbuffer_free_percent | 20 | | ndb_eventbuffer_max_alloc | 0 | | ndb_extra_logging | 1 | | ndb_force_send | ON | | ndb_fully_replicated | OFF | | ndb_index_stat_enable | ON | | ndb_index_stat_option | loop_enable=1000ms,loop_idle=1000ms, loop_busy=100ms,update_batch=1,read_batch=4,idle_batch=32,check_batch=8, check_delay=10m,delete_batch=8,clean_delay=1m,error_batch=4,error_delay=1m, evict_batch=8,evict_delay=1m,cache_limit=32M,cache_lowpct=90,zero_total=0 | | ndb_join_pushdown | ON | | ndb_log_apply_status | OFF | | ndb_log_bin | OFF | | ndb_log_binlog_index | ON | | ndb_log_empty_epochs | OFF | | ndb_log_empty_update | OFF | | ndb_log_exclusive_reads | OFF | | ndb_log_orig | OFF | | ndb_log_transaction_id | OFF | | ndb_log_update_as_write | ON | | ndb_log_update_minimal | OFF | | ndb_log_updated_only | ON | | ndb_metadata_check | ON | | ndb_metadata_check_interval | 60 | | ndb_metadata_sync | OFF | | ndb_mgmd_host | 127.0.0.1 | | ndb_nodeid | 0 | | ndb_optimization_delay | 10 | | ndb_optimized_node_selection | 3 | | ndb_read_backup | ON | | ndb_recv_thread_activation_threshold | 8 | | ndb_recv_thread_cpu_mask | | | ndb_report_thresh_binlog_epoch_slip | 10 | | ndb_report_thresh_binlog_mem_usage | 10 | | ndb_row_checksum | 1 | | ndb_schema_dist_lock_wait_timeout | 30 | | ndb_schema_dist_timeout | 120 | | ndb_schema_dist_upgrade_allowed | ON | | ndb_show_foreign_key_mock_tables | OFF | | ndb_slave_conflict_role | NONE | | ndb_table_no_logging | OFF | | ndb_table_temporary | OFF | | ndb_use_copying_alter_table | OFF | | ndb_use_exact_count | OFF | | ndb_use_transactions | ON | | ndb_version | 524308 | | ndb_version_string | ndb-9.0.0 | | ndb_wait_connected | 30 | | ndb_wait_setup | 30 | | ndbinfo_database | ndbinfo | | ndbinfo_max_bytes | 0 | | ndbinfo_max_rows | 10 | | ndbinfo_offline | OFF | | ndbinfo_show_hidden | OFF | | ndbinfo_table_prefix | ndb$ | | ndbinfo_version | 524308 | +--------------------------------------+---------------------------------------+與
SHOW VARIABLES語法的情況不同，可以選擇個別欄。例如mysql> SELECT VARIABLE_VALUE -> FROM performance_schema.global_variables -> WHERE VARIABLE_NAME = 'ndb_force_send'; +----------------+ | VARIABLE_VALUE | +----------------+ | ON | +----------------+此處顯示一個更有用的查詢
mysql> SELECT VARIABLE_NAME AS Name, VARIABLE_VALUE AS Value > FROM performance_schema.global_variables > WHERE VARIABLE_NAME > IN ('version', 'ndb_version', > 'ndb_version_string', 'ndbinfo_version'); +--------------------+---------------+ | Name | Value | +--------------------+---------------+ | ndb_version | 524544 | | ndb_version_string | ndb-8.4.0 | | ndbinfo_version | 524544 | | version | 8.4.0-cluster | +--------------------+---------------+ 4 rows in set (0.00 sec)如需更多資訊，請參閱第 29.12.15 節，「Performance Schema 狀態變數資料表」，以及第 7.1.8 節，「伺服器系統變數」。
此語法會立即顯示 MySQL 伺服器是否作為叢集 SQL 節點，如果是，則提供 MySQL 伺服器的叢集節點 ID、它所連線的叢集管理伺服器的主機名稱和連接埠，以及叢集中的資料節點數量，如下所示
mysql> SHOW STATUS LIKE 'NDB%'; +----------------------------------------------+-------------------------------+ | Variable_name | Value | +----------------------------------------------+-------------------------------+ | Ndb_metadata_detected_count | 0 | | Ndb_cluster_node_id | 100 | | Ndb_config_from_host | 127.0.0.1 | | Ndb_config_from_port | 1186 | | Ndb_number_of_data_nodes | 2 | | Ndb_number_of_ready_data_nodes | 2 | | Ndb_connect_count | 0 | | Ndb_execute_count | 0 | | Ndb_scan_count | 0 | | Ndb_pruned_scan_count | 0 | | Ndb_schema_locks_count | 0 | | Ndb_api_wait_exec_complete_count_session | 0 | | Ndb_api_wait_scan_result_count_session | 0 | | Ndb_api_wait_meta_request_count_session | 1 | | Ndb_api_wait_nanos_count_session | 163446 | | Ndb_api_bytes_sent_count_session | 60 | | Ndb_api_bytes_received_count_session | 28 | | Ndb_api_trans_start_count_session | 0 | | Ndb_api_trans_commit_count_session | 0 | | Ndb_api_trans_abort_count_session | 0 | | Ndb_api_trans_close_count_session | 0 | | Ndb_api_pk_op_count_session | 0 | | 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 | 0 | | Ndb_api_trans_local_read_row_count_session | 0 | | Ndb_api_adaptive_send_forced_count_session | 0 | | Ndb_api_adaptive_send_unforced_count_session | 0 | | Ndb_api_adaptive_send_deferred_count_session | 0 | | Ndb_trans_hint_count_session | 0 | | Ndb_sorted_scan_count | 0 | | Ndb_pushed_queries_defined | 0 | | Ndb_pushed_queries_dropped | 0 | | Ndb_pushed_queries_executed | 0 | | Ndb_pushed_reads | 0 | | Ndb_last_commit_epoch_server | 37632503447571 | | Ndb_last_commit_epoch_session | 0 | | Ndb_system_name | MC_20191126162038 | | 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_slave_max_replicated_epoch | 0 | | Ndb_api_wait_exec_complete_count | 4 | | Ndb_api_wait_scan_result_count | 7 | | Ndb_api_wait_meta_request_count | 172 | | Ndb_api_wait_nanos_count | 1083548094028 | | Ndb_api_bytes_sent_count | 4640 | | Ndb_api_bytes_received_count | 109356 | | Ndb_api_trans_start_count | 4 | | Ndb_api_trans_commit_count | 1 | | Ndb_api_trans_abort_count | 1 | | Ndb_api_trans_close_count | 4 | | Ndb_api_pk_op_count | 2 | | Ndb_api_uk_op_count | 0 | | Ndb_api_table_scan_count | 1 | | Ndb_api_range_scan_count | 1 | | Ndb_api_pruned_scan_count | 0 | | Ndb_api_scan_batch_count | 1 | | Ndb_api_read_row_count | 3 | | Ndb_api_trans_local_read_row_count | 2 | | Ndb_api_adaptive_send_forced_count | 1 | | Ndb_api_adaptive_send_unforced_count | 5 | | 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_metadata_excluded_count | 0 | | Ndb_metadata_synced_count | 0 | | Ndb_conflict_fn_max | 0 | | Ndb_conflict_fn_old | 0 | | Ndb_conflict_fn_max_del_win | 0 | | Ndb_conflict_fn_epoch | 0 | | Ndb_conflict_fn_epoch_trans | 0 | | Ndb_conflict_fn_epoch2 | 0 | | Ndb_conflict_fn_epoch2_trans | 0 | | Ndb_conflict_trans_row_conflict_count | 0 | | Ndb_conflict_trans_row_reject_count | 0 | | Ndb_conflict_trans_reject_count | 0 | | Ndb_conflict_trans_detect_iter_count | 0 | | Ndb_conflict_trans_conflict_commit_count | 0 | | Ndb_conflict_epoch_delete_delete_count | 0 | | Ndb_conflict_reflected_op_prepare_count | 0 | | Ndb_conflict_reflected_op_discard_count | 0 | | Ndb_conflict_refresh_op_count | 0 | | Ndb_conflict_last_conflict_epoch | 0 | | Ndb_conflict_last_stable_epoch | 0 | | Ndb_index_stat_status | allow:1,enable:1,busy:0, loop:1000,list:(new:0,update:0,read:0,idle:0,check:0,delete:0,error:0,total:0), analyze:(queue:0,wait:0),stats:(nostats:0,wait:0),total:(analyze:(all:0,error:0), query:(all:0,nostats:0,error:0),event:(act:0,skip:0,miss:0),cache:(refresh:0, clean:0,pinned:0,drop:0,evict:0)),cache:(query:0,clean:0,drop:0,evict:0, usedpct:0.00,highpct:0.00) | | Ndb_index_stat_cache_query | 0 | | Ndb_index_stat_cache_clean | 0 | +----------------------------------------------+-------------------------------+如果 MySQL 伺服器使用
NDB支援建置，但目前未連接到叢集，則此語法輸出中的每一列都會在Value欄中包含零或空字串。SELECT * FROM performance_schema.global_status WHERE VARIABLE_NAME LIKE 'NDB%'此語法提供與前一項討論的
SHOW STATUS語法類似的輸出。與SHOW STATUS的情況不同，可以使用SELECT語法以 SQL 格式提取值，以便在指令碼中使用，以進行監控和自動化。如需更多資訊，請參閱第 29.12.15 節，「Performance Schema 狀態變數資料表」。
SELECT * FROM INFORMATION_SCHEMA.PLUGINS WHERE PLUGIN_NAME LIKE 'NDB%'此語法顯示來自 Information Schema
PLUGINS資料表的資訊，這些資訊關於與 NDB 叢集相關聯的外掛程式，例如版本、作者和授權，如下所示mysql> SELECT * FROM INFORMATION_SCHEMA.PLUGINS > WHERE PLUGIN_NAME LIKE 'NDB%'\G *************************** 1. row *************************** PLUGIN_NAME: ndbcluster PLUGIN_VERSION: 1.0 PLUGIN_STATUS: ACTIVE PLUGIN_TYPE: STORAGE ENGINE PLUGIN_TYPE_VERSION: 90000.0 PLUGIN_LIBRARY: NULL PLUGIN_LIBRARY_VERSION: NULL PLUGIN_AUTHOR: Oracle Corporation PLUGIN_DESCRIPTION: Clustered, fault-tolerant tables PLUGIN_LICENSE: GPL LOAD_OPTION: ON *************************** 2. row *************************** PLUGIN_NAME: ndbinfo PLUGIN_VERSION: 0.1 PLUGIN_STATUS: ACTIVE PLUGIN_TYPE: STORAGE ENGINE PLUGIN_TYPE_VERSION: 90000.0 PLUGIN_LIBRARY: NULL PLUGIN_LIBRARY_VERSION: NULL PLUGIN_AUTHOR: Oracle Corporation PLUGIN_DESCRIPTION: MySQL Cluster system information storage engine PLUGIN_LICENSE: GPL LOAD_OPTION: ON *************************** 3. row *************************** PLUGIN_NAME: ndb_transid_mysql_connection_map PLUGIN_VERSION: 0.1 PLUGIN_STATUS: ACTIVE PLUGIN_TYPE: INFORMATION SCHEMA PLUGIN_TYPE_VERSION: 90000.0 PLUGIN_LIBRARY: NULL PLUGIN_LIBRARY_VERSION: NULL PLUGIN_AUTHOR: Oracle Corporation PLUGIN_DESCRIPTION: Map between MySQL connection ID and NDB transaction ID PLUGIN_LICENSE: GPL LOAD_OPTION: ON您也可以使用
SHOW PLUGINS語法來顯示此資訊，但該語法的輸出無法輕易篩選。另請參閱MySQL 外掛程式 API，其中說明PLUGINS資料表中的資訊取得位置和方式。
您也可以查詢 ndbinfo 資訊資料庫中的資料表，以取得有關許多 NDB 叢集操作的即時資料。請參閱第 25.6.17 節，「ndbinfo：NDB 叢集資訊資料庫」。