21.5.16 快速参考:NDB 群集 SQL 语句

本节讨论了一些 SQL 语句,这些语句在 Management 和监视连接到 NDB 群集的 MySQL 服务器方面可能很有用,并在某些情况下提供了有关群集本身的信息。

该语句的输出包含有关服务器与群集的连接,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,请参见第 13.7.5.15 节“ SHOW ENGINE 语句”

该语句可用于确定 MySQL 服务器中是否启用了集群支持,如果启用,则是否处于活动状态。

有关更多详细信息,请参见第 13.7.5.16 节“ SHOW ENGINES 语句”

Note

该语句不支持LIKE子句。但是,您可以使用LIKE来过滤针对INFORMATION_SCHEMA.ENGINEStable 的查询,如下一项所述。

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

这等效于SHOW ENGINES,但使用INFORMATION_SCHEMA数据库的ENGINEStable。与SHOW ENGINES语句不同,可以使用LIKE子句过滤结果,并选择特定的列以获得可能在脚本中使用的信息。例如,以下查询显示服务器是否使用NDB支持构建,如果支持,则是否启用:

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

有关更多信息,请参见第 24.7 节“ INFORMATION_SCHEMA ENGINEStable”

  • SHOW VARIABLES LIKE 'NDB%'

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

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-7.6.13                            |
| 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)

有关更多信息,请参见第 5.1.7 节“服务器系统变量”

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

尽管 NDB 7.5 和 NDB 7.6 中已弃用该语句,但是如果启用了show_compatibility_56,则可以使用此语句(和其他访问INFORMATION_SCHEMA.GLOBAL_VARIABLEStable 的语句)。 (查询performance_schema.global_variablestable 是首选;请参阅下一项。)它等效于上一项中描述的SHOW VARIABLES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-7.6.13                            |
| 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语句不同,可以选择单个列。例如:

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

有关更多信息,请参见第 24.11 节,“ INFORMATION_SCHEMA GLOBAL_VARIABLES 和 SESSION_VARIABLEStable”第 5.1.7 节“服务器系统变量”。另请参见第 25.20 节“迁移到性能模式系统和状态变量 table”

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

该语句等效于上一项中描述的SHOW VARIABLES语句,并且在 NDB 7.5 和 NDB 7.6 中比查询INFORMATION_SCHEMA.GLOBAL_VARIABLEStable(现在已弃用;请参见上一项)更受欢迎。它提供的输出几乎与SHOW VARIABLES产生的输出相同,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-7.6.13                            |
| 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语句不同,可以选择单个列。例如:

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

这里显示了更有用的查询:

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-7.6.13        |
| ndbinfo_version    | 460301            |
| version            | 5.7.29-ndb-7.6.13 |
+--------------------+-------------------+

有关更多信息,请参见第 25.12.13 节,“性能架构系统变量 table”第 5.1.7 节“服务器系统变量”

  • SHOW STATUS LIKE 'NDB%'

此语句一目了然,显示 MySQL 服务器是否充当群集 SQL 节点,如果是,它将提供 MySQL 服务器的群集节点 ID,与其连接的群集 Management 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 服务器是使用群集支持构建的,但未连接到群集,则此语句输出中的所有行均包含零或空字符串。

另请参见第 13.7.5.35 节“ SHOW STATUS 语句”

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

尽管启用了show_compatibility_56以获得与上一项目中讨论的SHOW STATUS语句类似的输出,但可以在 NDB 7.5 和 NDB 7.6 中弃用该语句。首选方法是查询performance_schema.global_statustable(请参阅下一项)。与SHOW STATUS的情况不同,可以使用SELECT提取 SQL 中的值以用于脚本中以进行监视和自动化。

有关更多信息,请参见第 24.10 节,“ INFORMATION_SCHEMA GLOBAL_STATUS 和 SESSION_STATUStable”第 25.20 节“迁移到性能模式系统和状态变量 table”

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

该语句提供的输出与前面讨论的SHOW STATUS相似。与SHOW STATUS的情况不同,可以使用SELECT语句在 SQL 中提取值以用于脚本中以进行监视和自动化。

有关更多信息,请参见第 25.12.14 节,“性能模式状态变量 table”

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

此语句显示INFORMATION_SCHEMA.PLUGINStable 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: 50729.0
        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: 50729.0
        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语句显示此信息,但是该语句的输出无法轻松过滤。另请参见第 28.2 节“ MySQL 插件 API”,它描述了在何处以及如何获取PLUGINStable 中的信息。

您还可以查询ndbinfo信息数据库中的 table,以获取有关许多 NDB 群集操作的实时数据。参见第 21.5.14 节,“ ndbinfo:NDB 群集信息数据库”