The NDB Cluster Information Database (original) (raw)
21.6.15 ndbinfo: The NDB Cluster Information Database
ndbinfo is a database containing information specific to NDB Cluster.
This database contains a number of tables, each providing a different sort of data about NDB Cluster node status, resource usage, and operations. You can find more detailed information about each of these tables in the next several sections.
ndbinfo is included with NDB Cluster support in the MySQL Server; no special compilation or configuration steps are required; the tables are created by the MySQL Server when it connects to the cluster. You can verify thatndbinfo support is active in a given MySQL Server instance using SHOW PLUGINS; if ndbinfo support is enabled, you should see a row containing ndbinfo in theName column and ACTIVE in the Status column, as shown here (emphasized text):
mysql> SHOW PLUGINS;
+----------------------------------+--------+--------------------+---------+---------+
| Name | Status | Type | Library | License |
+----------------------------------+--------+--------------------+---------+---------+
| binlog | ACTIVE | STORAGE ENGINE | NULL | GPL |
| mysql_native_password | ACTIVE | AUTHENTICATION | NULL | GPL |
| sha256_password | ACTIVE | AUTHENTICATION | NULL | GPL |
| MRG_MYISAM | ACTIVE | STORAGE ENGINE | NULL | GPL |
| MEMORY | ACTIVE | STORAGE ENGINE | NULL | GPL |
| CSV | ACTIVE | STORAGE ENGINE | NULL | GPL |
| MyISAM | ACTIVE | STORAGE ENGINE | NULL | GPL |
| InnoDB | ACTIVE | STORAGE ENGINE | NULL | GPL |
| INNODB_TRX | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_LOCKS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_LOCK_WAITS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_CMP | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_CMP_RESET | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_CMPMEM | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_CMPMEM_RESET | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_CMP_PER_INDEX | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_CMP_PER_INDEX_RESET | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_BUFFER_PAGE | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_BUFFER_PAGE_LRU | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_BUFFER_POOL_STATS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_TEMP_TABLE_INFO | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_METRICS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_FT_DEFAULT_STOPWORD | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_FT_DELETED | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_FT_BEING_DELETED | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_FT_CONFIG | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_FT_INDEX_CACHE | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_FT_INDEX_TABLE | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_TABLES | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_TABLESTATS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_INDEXES | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_COLUMNS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_FIELDS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_FOREIGN | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_FOREIGN_COLS | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_TABLESPACES | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_DATAFILES | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| INNODB_SYS_VIRTUAL | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| PERFORMANCE_SCHEMA | ACTIVE | STORAGE ENGINE | NULL | GPL |
| ndbCluster | ACTIVE | STORAGE ENGINE | NULL | GPL |
| ndbinfo | ACTIVE | STORAGE ENGINE | NULL | GPL |
| ndb_transid_mysql_connection_map | ACTIVE | INFORMATION SCHEMA | NULL | GPL |
| BLACKHOLE | ACTIVE | STORAGE ENGINE | NULL | GPL |
| ARCHIVE | ACTIVE | STORAGE ENGINE | NULL | GPL |
| partition | ACTIVE | STORAGE ENGINE | NULL | GPL |
| ngram | ACTIVE | FTPARSER | NULL | GPL |
+----------------------------------+--------+--------------------+---------+---------+
46 rows in set (0.00 sec) You can also do this by checking the output ofSHOW ENGINES for a line includingndbinfo in the Engine column and YES in the Support column, as shown here (emphasized text):
mysql> SHOW ENGINES\G
*************************** 1. row ***************************
Engine: ndbcluster
Support: YES
Comment: Clustered, fault-tolerant tables
Transactions: YES
XA: NO
Savepoints: NO
*************************** 2. row ***************************
Engine: CSV
Support: YES
Comment: CSV storage engine
Transactions: NO
XA: NO
Savepoints: NO
*************************** 3. row ***************************
Engine: InnoDB
Support: DEFAULT
Comment: Supports transactions, row-level locking, and foreign keys
Transactions: YES
XA: YES
Savepoints: YES
*************************** 4. row ***************************
Engine: BLACKHOLE
Support: YES
Comment: /dev/null storage engine (anything you write to it disappears)
Transactions: NO
XA: NO
Savepoints: NO
*************************** 5. row ***************************
Engine: MyISAM
Support: YES
Comment: MyISAM storage engine
Transactions: NO
XA: NO
Savepoints: NO
*************************** 6. row ***************************
Engine: MRG_MYISAM
Support: YES
Comment: Collection of identical MyISAM tables
Transactions: NO
XA: NO
Savepoints: NO
*************************** 7. row ***************************
Engine: ARCHIVE
Support: YES
Comment: Archive storage engine
Transactions: NO
XA: NO
Savepoints: NO
*************************** 8. row ***************************
Engine: ndbinfo
Support: YES
Comment: NDB Cluster system information storage engine
Transactions: NO
XA: NO
Savepoints: NO
*************************** 9. row ***************************
Engine: PERFORMANCE_SCHEMA
Support: YES
Comment: Performance Schema
Transactions: NO
XA: NO
Savepoints: NO
*************************** 10. row ***************************
Engine: MEMORY
Support: YES
Comment: Hash based, stored in memory, useful for temporary tables
Transactions: NO
XA: NO
Savepoints: NO
10 rows in set (0.00 sec) If ndbinfo support is enabled, then you can access ndbinfo using SQL statements inmysql or another MySQL client. For example, you can see ndbinfo listed in the output ofSHOW DATABASES, as shown here (emphasized text):
mysql> SHOW DATABASES;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| ndbinfo |
| performance_schema |
| sys |
+--------------------+
5 rows in set (0.04 sec) If the mysqld process was not started with the--ndbcluster option,ndbinfo is not available and is not displayed by SHOW DATABASES. Ifmysqld was formerly connected to an NDB Cluster but the cluster becomes unavailable (due to events such as cluster shutdown, loss of network connectivity, and so forth),ndbinfo and its tables remain visible, but an attempt to access any tables (other than blocks or config_params) fails with Got error 157 'Connection to NDB failed' from NDBINFO.
With the exception of the blocks and config_params tables, what we refer to as ndbinfo “tables” are actually views generated from internalNDB tables not normally visible to the MySQL Server. You can make these tables visible by setting thendbinfo_show_hidden system variable to ON (or 1), but this is normally not necessary.
All ndbinfo tables are read-only, and are generated on demand when queried. Because many of them are generated in parallel by the data nodes while other are specific to a given SQL node, they are not guaranteed to provide a consistent snapshot.
In addition, pushing down of joins is not supported onndbinfo tables; so joining largendbinfo tables can require transfer of a large amount of data to the requesting API node, even when the query makes use of a WHERE clause.
ndbinfo tables are not included in the query cache. (Bug #59831)
You can select the ndbinfo database with aUSE statement, and then issue aSHOW TABLES statement to obtain a list of tables, just as for any other database, like this:
mysql> USE ndbinfo;
Database changed
mysql> SHOW TABLES;
+---------------------------------+
| Tables_in_ndbinfo |
+---------------------------------+
| arbitrator_validity_detail |
| arbitrator_validity_summary |
| blocks |
| cluster_locks |
| cluster_operations |
| cluster_transactions |
| config_nodes |
| config_params |
| config_values |
| counters |
| cpustat |
| cpustat_1sec |
| cpustat_20sec |
| cpustat_50ms |
| dict_obj_info |
| dict_obj_types |
| disk_write_speed_aggregate |
| disk_write_speed_aggregate_node |
| disk_write_speed_base |
| diskpagebuffer |
| error_messages |
| locks_per_fragment |
| logbuffers |
| logspaces |
| membership |
| memory_per_fragment |
| memoryusage |
| nodes |
| operations_per_fragment |
| processes |
| resources |
| restart_info |
| server_locks |
| server_operations |
| server_transactions |
| table_distribution_status |
| table_fragments |
| table_info |
| table_replicas |
| tc_time_track_stats |
| threadblocks |
| threads |
| threadstat |
| transporters |
+---------------------------------+
44 rows in set (0.00 sec) In NDB 7.5.0 (and later), all ndbinfo tables use the NDB storage engine; however, anndbinfo entry still appears in the output ofSHOW ENGINES andSHOW PLUGINS as described previously.
The config_values table was added in NDB 7.5.0.
The cpustat,cpustat_50ms,cpustat_1sec,cpustat_20sec, andthreads tables were added in NDB 7.5.2.
The cluster_locks,locks_per_fragment, andserver_locks tables were added in NDB 7.5.3.
The dict_obj_info,table_distribution_status,table_fragments,table_info, andtable_replicas tables were added in NDB 7.5.4.
The config_nodes andprocesses tables were added in NDB 7.5.7.
The error_messages table was added in NDB 7.6.
You can execute SELECT statements against these tables, just as you would normally expect:
mysql> SELECT * FROM memoryusage;
+---------+---------------------+--------+------------+------------+-------------+
| node_id | memory_type | used | used_pages | total | total_pages |
+---------+---------------------+--------+------------+------------+-------------+
| 5 | Data memory | 753664 | 23 | 1073741824 | 32768 |
| 5 | Index memory | 163840 | 20 | 1074003968 | 131104 |
| 5 | Long message buffer | 2304 | 9 | 67108864 | 262144 |
| 6 | Data memory | 753664 | 23 | 1073741824 | 32768 |
| 6 | Index memory | 163840 | 20 | 1074003968 | 131104 |
| 6 | Long message buffer | 2304 | 9 | 67108864 | 262144 |
+---------+---------------------+--------+------------+------------+-------------+
6 rows in set (0.02 sec)More complex queries, such as the two followingSELECT statements using thememoryusage table, are possible:
mysql> SELECT SUM(used) as 'Data Memory Used, All Nodes'
> FROM memoryusage
> WHERE memory_type = 'Data memory';
+-----------------------------+
| Data Memory Used, All Nodes |
+-----------------------------+
| 6460 |
+-----------------------------+
1 row in set (0.37 sec)
mysql> SELECT SUM(max) as 'Total IndexMemory Available'
> FROM memoryusage
> WHERE memory_type = 'Index memory';
+-----------------------------+
| Total IndexMemory Available |
+-----------------------------+
| 25664 |
+-----------------------------+
1 row in set (0.33 sec)ndbinfo table and column names are case-sensitive (as is the name of the ndbinfo database itself). These identifiers are in lowercase. Trying to use the wrong lettercase results in an error, as shown in this example:
mysql> SELECT * FROM nodes;
+---------+--------+---------+-------------+
| node_id | uptime | status | start_phase |
+---------+--------+---------+-------------+
| 1 | 13602 | STARTED | 0 |
| 2 | 16 | STARTED | 0 |
+---------+--------+---------+-------------+
2 rows in set (0.04 sec)
mysql> SELECT * FROM Nodes;
ERROR 1146 (42S02): Table 'ndbinfo.Nodes' doesn't existmysqldump ignores thendbinfo database entirely, and excludes it from any output. This is true even when using the--databases or--all-databases option.
NDB Cluster also maintains tables in theINFORMATION_SCHEMA information database, including the FILES table which contains information about files used for NDB Cluster Disk Data storage, and thendb_transid_mysql_connection_map table, which shows the relationships between transactions, transaction coordinators, and NDB Cluster API nodes. For more information, see the descriptions of the tables orSection 21.6.16, “INFORMATION_SCHEMA Tables for NDB Cluster”.