MySQL :: MySQL 8.0 Reference Manual :: 25.6.19 Quick Reference: NDB Cluster SQL Statements (original) (raw)
25.6.19 Quick Reference: NDB Cluster SQL Statements
This section discusses several SQL statements that can prove useful in managing and monitoring a MySQL server that is connected to an NDB Cluster, and in some cases provide information about the cluster itself.
- SHOW ENGINE NDB STATUS,SHOW ENGINE NDBCLUSTER STATUS
The output of this statement contains information about the server's connection to the cluster, creation and usage of NDB Cluster objects, and binary logging for NDB Cluster replication.
See Section 15.7.7.15, “SHOW ENGINE Statement”, for a usage example and more detailed information. - SHOW ENGINES
This statement can be used to determine whether or not clustering support is enabled in the MySQL server, and if so, whether it is active.
See Section 15.7.7.16, “SHOW ENGINES Statement”, for more detailed information.
Note
This statement does not support aLIKE clause. However, you can use LIKE to filter queries against the Information SchemaENGINES table, as discussed in the next item. SELECT * FROM INFORMATION_SCHEMA.ENGINES [WHERE ENGINE LIKE 'NDB%']
This is the equivalent of SHOW ENGINES, but uses theENGINES table of theINFORMATION_SCHEMAdatabase. Unlike the case with the SHOW ENGINES statement, it is possible to filter the results using aLIKE clause, and to select specific columns to obtain information that may be of use in scripts. For example, the following query shows whether the server was built with NDB support and, if so, whether it is enabled:
mysql> SELECT ENGINE, SUPPORT FROM INFORMATION_SCHEMA.ENGINES
-> WHERE ENGINE LIKE 'NDB%';
+------------+---------+
| ENGINE | SUPPORT |
+------------+---------+
| ndbcluster | YES |
| ndbinfo | YES |
+------------+---------+ If NDB support is not enabled, the preceding query returns an empty set. SeeSection 28.3.13, “The INFORMATION_SCHEMA ENGINES Table”, for more information.
SHOW VARIABLES LIKE 'NDB%'
This statement provides a list of most server system variables relating to the NDB storage engine, and their values, as shown here:
mysql> SHOW VARIABLES LIKE 'NDB%';
+--------------------------------------+---------------------------------------+
| Variable_name | 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-8.0.42 |
| 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 |
+--------------------------------------+---------------------------------------+ See Section 7.1.8, “Server System Variables”, for more information.
SELECT * FROM performance_schema.global_variables WHERE VARIABLE_NAME LIKE 'NDB%'
This statement is the equivalent of theSHOW VARIABLES statement described in the previous item, and provides almost identical output, as shown here:
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-8.0.42 |
| 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 |
+--------------------------------------+---------------------------------------+ Unlike the case with the SHOW VARIABLES statement, it is possible to select individual columns. For example:
mysql> SELECT VARIABLE_VALUE
-> FROM performance_schema.global_variables
-> WHERE VARIABLE_NAME = 'ndb_force_send';
+----------------+
| VARIABLE_VALUE |
+----------------+
| ON |
+----------------+ A more useful query is shown here:
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 | 524317 |
| ndb_version_string | ndb-8.0.29 |
| ndbinfo_version | 524317 |
| version | 8.0.29-cluster |
+--------------------+----------------+
4 rows in set (0.00 sec) For more information, seeSection 29.12.15, “Performance Schema Status Variable Tables”, and Section 7.1.8, “Server System Variables”.
SHOW STATUS LIKE 'NDB%'
This statement shows at a glance whether or not the MySQL server is acting as a cluster SQL node, and if so, it provides the MySQL server's cluster node ID, the host name and port for the cluster management server to which it is connected, and the number of data nodes in the cluster, as shown here:
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 |
+----------------------------------------------+-------------------------------+ If the MySQL server was built with NDB support, but it is not currently connected to a cluster, every row in the output of this statement contains a zero or an empty string for the Value column.
See also Section 15.7.7.37, “SHOW STATUS Statement”.
SELECT * FROM performance_schema.global_status WHERE VARIABLE_NAME LIKE 'NDB%'
This statement provides similar output to theSHOW STATUS statement discussed in the previous item. Unlike the case withSHOW STATUS, it is possible using SELECT statements to extract values in SQL for use in scripts for monitoring and automation purposes.
For more information, seeSection 29.12.15, “Performance Schema Status Variable Tables”.SELECT * FROM INFORMATION_SCHEMA.PLUGINS WHERE PLUGIN_NAME LIKE 'NDB%'
This statement displays information from the Information Schema PLUGINS table about plugins associated with NDB Cluster, such as version, author, and license, as shown here:
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: 80042.0
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: 80042.0
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: 80042.0
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 You can also use the SHOW PLUGINS statement to display this information, but the output from that statement cannot easily be filtered. See also The MySQL Plugin API, which describes where and how the information in thePLUGINS table is obtained.
You can also query the tables in thendbinfo information database for real-time data about many NDB Cluster operations. SeeSection 25.6.16, “ndbinfo: The NDB Cluster Information Database”.