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MySQL 8.0 参考手册  / 第 23 章 MySQL NDB Cluster 8.0  / 23.6 NDB Cluster的管理  /  21.6.17 快速参考:NDB Cluster SQL 语句

21.6.17 快速参考:NDB Cluster SQL 语句

本节讨论几个 SQL 语句,这些语句可以证明在管理和监视连接到 NDB Cluster 的 MySQL 服务器方面很有用,并且在某些情况下提供有关集群本身的信息。

  • SHOW ENGINE NDB STATUS, SHOW ENGINE NDBCLUSTER STATUS

    此语句的输出包含有关服务器与集群的连接、NDB Cluster 对象的创建和使用以及 NDB Cluster 复制的二进制日志记录的信息。

    有关用法示例和更多详细信息, 请参阅第 13.7.5.15 节,“SHOW ENGINE 语句” 。

  • SHOW ENGINES

    此语句可用于确定是否在 MySQL 服务器中启用了集群支持,如果启用,则它是否处于活动状态。

    有关更多详细信息, 请参阅第 13.7.5.16 节,“SHOW ENGINES 语句” 。

    笔记

    此语句不支持 LIKE子句。但是,您可以使用LIKE该表来过滤查询 INFORMATION_SCHEMA.ENGINES ,这将在下一项中讨论。

  • SELECT * FROM INFORMATION_SCHEMA.ENGINES [WHERE ENGINE LIKE 'NDB%']

    这相当于SHOW ENGINES,但使用数据库的 ENGINESINFORMATION_SCHEMA。与SHOW ENGINES 语句的情况不同,可以使用 LIKE子句过滤结果,并选择特定的列以获取可能在脚本中使用的信息。例如,以下查询显示服务器是否NDB支持构建,如果是,是否启用:

    mysql> SELECT SUPPORT FROM INFORMATION_SCHEMA.ENGINES
        ->   WHERE ENGINE LIKE 'NDB%';
    +---------+
    | support |
    +---------+
    | ENABLED |
    +---------+

    有关更多信息,请参阅第 24.3.7 节,“INFORMATION_SCHEMA ENGINES 表”

  • SHOW VARIABLES LIKE 'NDB%'

    此语句提供了与NDB存储引擎相关的大多数服务器系统变量的列表及其值,如下所示,使用 NDB 7.6:

    mysql> SHOW VARIABLES LIKE 'NDB%';
    +--------------------------------------+---------------------------------------+
    | Variable_name                        | Value                                 |
    +--------------------------------------+---------------------------------------+
    | ndb_allow_copying_alter_table        | ON                                    |
    | ndb_autoincrement_prefetch_sz        | 1                                     |
    | ndb_batch_size                       | 32768                                 |
    | ndb_blob_read_batch_bytes            | 65536                                 |
    | ndb_blob_write_batch_bytes           | 65536                                 |
    | ndb_cache_check_time                 | 0                                     |
    | 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                          | ON                                    |
    | 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_mgmd_host                        | 127.0.0.1                             |
    | ndb_nodeid                           | 0                                     |
    | ndb_optimization_delay               | 10                                    |
    | ndb_optimized_node_selection         | 3                                     |
    | ndb_read_backup                      | OFF                                   |
    | 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_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                          | 460301                                |
    | ndb_version_string                   | ndb-7.6.25                            |
    | 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                      | 460301                                |
    +--------------------------------------+---------------------------------------+
    61 rows in set (0.02 sec)

    有关详细信息,请参阅第 5.1.7 节,“服务器系统变量”

  • SELECT * FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES WHERE VARIABLE_NAME LIKE 'NDB%';

    尽管在 NDB 7.5 和 NDB 7.6 中已弃用,但 INFORMATION_SCHEMA.GLOBAL_VARIABLES如果show_compatibility_56启用,您可以使用此语句(以及其他访问表的语句)。(最好查询 performance_schema.global_variables 表;请参阅下一项。)它等同于上 SHOW VARIABLES一项中描述的语句,并提供几乎相同的输出,如下所示:

    mysql> SET @@global.show_compatibility_56=ON;
    Query OK, 0 rows affected (0.00 sec)
    
    mysql> SELECT * FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES
        ->   WHERE VARIABLE_NAME LIKE 'NDB%';
    
    mysql> SELECT * FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES WHERE VARIABLE_NAME LIKE 'NDB%';
    +--------------------------------------+---------------------------------------+
    | VARIABLE_NAME                        | VARIABLE_VALUE                        |
    +--------------------------------------+---------------------------------------+
    | NDB_CLUSTER_CONNECTION_POOL_NODEIDS  |                                       |
    | NDB_LOG_BINLOG_INDEX                 | ON                                    |
    | NDB_WAIT_SETUP                       | 30                                    |
    | NDB_ROW_CHECKSUM                     | 1                                     |
    | NDB_WAIT_CONNECTED                   | 30                                    |
    | NDB_USE_EXACT_COUNT                  | OFF                                   |
    | NDB_RECV_THREAD_ACTIVATION_THRESHOLD | 8                                     |
    | NDB_READ_BACKUP                      | OFF                                   |
    | NDB_EVENTBUFFER_MAX_ALLOC            | 0                                     |
    | NDBINFO_DATABASE                     | ndbinfo                               |
    | NDB_LOG_APPLY_STATUS                 | OFF                                   |
    | NDB_JOIN_PUSHDOWN                    | ON                                    |
    | NDB_RECV_THREAD_CPU_MASK             |                                       |
    | NDBINFO_VERSION                      | 460301                                |
    | NDB_CONNECTSTRING                    | 127.0.0.1                             |
    | NDB_TABLE_NO_LOGGING                 | OFF                                   |
    | NDB_LOG_UPDATED_ONLY                 | ON                                    |
    | NDB_VERSION                          | 460301                                |
    | NDB_LOG_UPDATE_MINIMAL               | OFF                                   |
    | NDB_OPTIMIZATION_DELAY               | 10                                    |
    | NDB_DEFAULT_COLUMN_FORMAT            | FIXED                                 |
    | NDB_LOG_UPDATE_AS_WRITE              | ON                                    |
    | NDB_SHOW_FOREIGN_KEY_MOCK_TABLES     | OFF                                   |
    | NDB_VERSION_STRING                   | ndb-7.6.25                            |
    | NDBINFO_OFFLINE                      | OFF                                   |
    | 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      |
    | NDBINFO_MAX_ROWS                     | 10                                    |
    | NDB_BATCH_SIZE                       | 32768                                 |
    | NDB_USE_TRANSACTIONS                 | ON                                    |
    | NDB_NODEID                           | 0                                     |
    | NDB_ALLOW_COPYING_ALTER_TABLE        | ON                                    |
    | NDB_SLAVE_CONFLICT_ROLE              | NONE                                  |
    | NDB_REPORT_THRESH_BINLOG_MEM_USAGE   | 10                                    |
    | NDB_FULLY_REPLICATED                 | OFF                                   |
    | NDB_MGMD_HOST                        | 127.0.0.1                             |
    | NDB_REPORT_THRESH_BINLOG_EPOCH_SLIP  | 10                                    |
    | NDBINFO_MAX_BYTES                    | 0                                     |
    | NDB_LOG_BIN                          | ON                                    |
    | NDBINFO_TABLE_PREFIX                 | ndb$                                  |
    | NDB_LOG_EMPTY_EPOCHS                 | OFF                                   |
    | NDB_LOG_ORIG                         | OFF                                   |
    | NDB_LOG_EXCLUSIVE_READS              | OFF                                   |
    | NDB_LOG_TRANSACTION_ID               | OFF                                   |
    | NDB_DATA_NODE_NEIGHBOUR              | 0                                     |
    | NDB_CLEAR_APPLY_STATUS               | ON                                    |
    | NDBINFO_SHOW_HIDDEN                  | OFF                                   |
    | NDB_INDEX_STAT_ENABLE                | ON                                    |
    | NDB_DISTRIBUTION                     | KEYHASH                               |
    | NDB_BLOB_WRITE_BATCH_BYTES           | 65536                                 |
    | NDB_DEFERRED_CONSTRAINTS             | 0                                     |
    | NDB_TABLE_TEMPORARY                  | OFF                                   |
    | NDB_EXTRA_LOGGING                    | 1                                     |
    | NDB_AUTOINCREMENT_PREFETCH_SZ        | 1                                     |
    | NDB_FORCE_SEND                       | ON                                    |
    | NDB_OPTIMIZED_NODE_SELECTION         | 3                                     |
    | NDB_CLUSTER_CONNECTION_POOL          | 1                                     |
    | NDB_EVENTBUFFER_FREE_PERCENT         | 20                                    |
    | NDB_USE_COPYING_ALTER_TABLE          | OFF                                   |
    | NDB_CACHE_CHECK_TIME                 | 0                                     |
    | NDB_BLOB_READ_BATCH_BYTES            | 65536                                 |
    | NDB_LOG_EMPTY_UPDATE                 | OFF                                   |
    +--------------------------------------+---------------------------------------+
    61 rows in set, 1 warning (0.00 sec)
    
    mysql> SHOW WARNINGS;
    +---------+------+-------------------------------------------------------------+
    | Level   | Code | Message                                                     |
    +---------+------+-------------------------------------------------------------+
    | Warning | 1287 | 'INFORMATION_SCHEMA.GLOBAL_VARIABLES' is deprecated and will
    be removed in a future release. Please use performance_schema.global_variables
    instead                                                                        |
    +---------+------+-------------------------------------------------------------+

    SHOW VARIABLES语句的情况不同,可以选择单独的列。例如:

    mysql> SELECT VARIABLE_VALUE 
        ->   FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES
        ->   WHERE VARIABLE_NAME = 'ndb_force_send';
    +----------------+
    | VARIABLE_VALUE |
    +----------------+
    | ON             |
    +----------------+

    有关详细信息,请参阅第 24.3.11 节,“INFORMATION_SCHEMA GLOBAL_VARIABLES 和 SESSION_VARIABLES 表”第 5.1.7 节,“服务器系统变量”。另见 第 25.20 节,“迁移到性能模式系统和状态变量表”

  • SELECT * FROM performance_schema.global_variables WHERE VARIABLE_NAME LIKE 'NDB%'

    此语句等效于 SHOW VARIABLES上一项中描述的语句,在 NDB 7.5 和 NDB 7.6 中首选查询 INFORMATION_SCHEMA.GLOBAL_VARIABLES表(现已弃用;请参阅上一项)。它提供的输出几乎与 生成的输出相同SHOW VARIABLES,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        | 1                                     |
    | ndb_batch_size                       | 32768                                 |
    | ndb_blob_read_batch_bytes            | 65536                                 |
    | ndb_blob_write_batch_bytes           | 65536                                 |
    | ndb_cache_check_time                 | 0                                     |
    | 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                          | ON                                    |
    | 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_mgmd_host                        | 127.0.0.1                             |
    | ndb_nodeid                           | 0                                     |
    | ndb_optimization_delay               | 10                                    |
    | ndb_optimized_node_selection         | 3                                     |
    | ndb_read_backup                      | OFF                                   |
    | 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_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                          | 460301                                |
    | ndb_version_string                   | ndb-7.6.25                            |
    | 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                      | 460301                                |
    +--------------------------------------+---------------------------------------+

    SHOW VARIABLES语句的情况不同,可以选择单独的列。例如:

    mysql> SELECT VARIABLE_VALUE 
        ->   FROM performance_schema.global_variables
        ->   WHERE VARIABLE_NAME = 'ndb_force_send';
    +----------------+
    | VARIABLE_VALUE |
    +----------------+
    | ON             |
    +----------------+

    此处显示了一个更有用的查询:

    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        | 460301            |
    | ndb_version_string | ndb-7.6.25        |
    | ndbinfo_version    | 460301            |
    | version            | 5.7.40-ndb-7.6.25 |
    +--------------------+-------------------+

    有关详细信息,请参阅 第 25.12.13 节,“性能模式系统变量表”第 5.1.7 节,“服务器系统变量”

  • SHOW STATUS LIKE 'NDB%'

    该语句一目了然地显示了MySQL服务器是否充当集群SQL节点,如果是,它提供了MySQL服务器的集群节点ID,它所连接的集群管理服务器的主机名和端口,以及集群中数据节点的数量,如下所示:

    mysql> SHOW STATUS LIKE 'NDB%';
    +----------------------------------------------+-------------------------------+
    | Variable_name                                | Value                         |
    +----------------------------------------------+-------------------------------+
    | Ndb_api_wait_exec_complete_count             | 2                             |
    | Ndb_api_wait_scan_result_count               | 5                             |
    | Ndb_api_wait_meta_request_count              | 54                            |
    | Ndb_api_wait_nanos_count                     | 1849442202547                 |
    | Ndb_api_bytes_sent_count                     | 2044                          |
    | Ndb_api_bytes_received_count                 | 81384                         |
    | Ndb_api_trans_start_count                    | 2                             |
    | Ndb_api_trans_commit_count                   | 1                             |
    | Ndb_api_trans_abort_count                    | 0                             |
    | Ndb_api_trans_close_count                    | 2                             |
    | Ndb_api_pk_op_count                          | 1                             |
    | 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                     | 2                             |
    | Ndb_api_read_row_count                       | 4                             |
    | Ndb_api_trans_local_read_row_count           | 2                             |
    | Ndb_api_adaptive_send_forced_count           | 0                             |
    | Ndb_api_adaptive_send_unforced_count         | 3                             |
    | 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_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_event_data_count_injector            | 0                             |
    | Ndb_api_event_nondata_count_injector         | 0                             |
    | Ndb_api_event_bytes_count_injector           | 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      | 0                             |
    | Ndb_api_wait_nanos_count_session             | 0                             |
    | Ndb_api_bytes_sent_count_session             | 0                             |
    | Ndb_api_bytes_received_count_session         | 0                             |
    | 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_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                 | 29347511533580                |
    | Ndb_last_commit_epoch_session                | 0                             |
    | Ndb_system_name                              | MC_20191209172820             |
    | 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 服务器构建时支持集群,但未连接到集群,则此语句输出中的所有行都包含零或空字符串。

    另见第 13.7.5.35 节,“SHOW STATUS 语句”

  • SELECT * FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME LIKE 'NDB%';

    此语句虽然在 NDB 7.5 和 NDB 7.6 中已弃用,但如果启用以获得与上一项中讨论的语句show_compatibility_56类似的输出 ,则可以使用 ;SHOW STATUS首选方法是查询 performance_schema.global_status 表(见下一项)。与 的情况不同 SHOW STATUS,可以使用SELECT来提取 SQL 中的值,以便在用于监视和自动化目的的脚本中使用。

    有关更多信息,请参阅第 24.3.10 节,“INFORMATION_SCHEMA GLOBAL_STATUS 和 SESSION_STATUS 表”,以及 第 25.20 节,“迁移到性能模式系统和状态变量表”

  • SELECT * FROM performance_schema.global_status WHERE VARIABLE_NAME LIKE 'NDB%'

    SHOW STATUS此语句提供与前面讨论 的语句类似的输出 。与 的情况不同SHOW STATUS,可以使用 SELECT语句来提取 SQL 中的值,以便在用于监视和自动化目的的脚本中使用。

    有关详细信息,请参阅 第 25.12.14 节,“性能模式状态变量表”

  • SELECT * FROM INFORMATION_SCHEMA.PLUGINS WHERE PLUGIN_NAME LIKE 'NDB%'

    此语句显示 INFORMATION_SCHEMA.PLUGINS表中有关与 NDB Cluster 关联的插件的信息,例如版本、作者和许可证,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: 50729.0
            PLUGIN_LIBRARY: NULL
    PLUGIN_LIBRARY_VERSION: NULL
             PLUGIN_AUTHOR: MySQL AB
        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: 50740.0
            PLUGIN_LIBRARY: NULL
    PLUGIN_LIBRARY_VERSION: NULL
             PLUGIN_AUTHOR: Sun Microsystems Inc.
        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: 50740.0
            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

    您也可以使用该SHOW PLUGINS语句来显示此信息,但无法轻易过滤该语句的输出。另请参阅MySQL 插件 API,它描述了从何处以及如何获取 PLUGINS表中的信息。

您还可以查询 ndbinfo信息数据库中的表以获取有关许多 NDB Cluster 操作的实时数据。请参阅 第 21.6.15 节,“ndbinfo:NDB Cluster 信息数据库”