17.5.10.14 The ndbinfo pools Table

Important

This table was part of the original ndbinfo implementation, but was later removed (in MySQL Cluster NDB 7.1.3). The information in this section is now obsolete, and subject to removal in a future version of the documentation.

The pools table was originally intended to provide information about NDB memory pool usage, but was later removed.

For each column, this table shows the name, data type, and a brief description of each ndbinfo.pools column (as it appeared prior to MySQL Cluster NDB 7.1.3). Additional information can be found in the notes afterward.

Column NameTypeDescription
node_idintegerThe data node's node ID.
block_namestringName of the NDB kernel block using this pool.
block_instanceintegerKernel block instance ID.
pool_namestringThe name of the pool.
usedintegerAmount of the pool in use.
totalintegerTotal size of the pool.
highintegerThe maximum used from this pool (since the node was last started).
entry_sizeintegerThe size of each object, in bytes.
param_name1stringName of a configuration parameter associated with this pool (or NULL); see text.
param_name2stringName of a configuration parameter associated with this pool (or NULL); see text.
param_name3stringName of a configuration parameter associated with this pool (or NULL); see text.
param_name4stringName of a configuration parameter associated with this pool (or NULL); see text.

The columns param_name1, param_name2, param_name3, and param_name4 contain names of configuration parameters that are associated with a given pool. If no parameters are associated with the pool, then all 4 of these columns are NULL. For pools that are associated with configuration parameters, these columns are filled with non-NULL values, but not in any particular order.

You can use a query such as the one shown here to generate a table showing the associations of pools, NDB kernel blocks, and (where applicable) configuration parameters:

SELECT
    DISTINCT(pool_name) as 'Pool',
    block_name as 'Block',
    IF(
        (param_name1 && param_name2 && param_name3 && param_name4) IS NULL,
        '[NONE]',
        REPLACE(
            TRIM(
                CONCAT(
                    IFNULL(param_name1, ''),
                    IFNULL(CONCAT(' ', param_name2), ''),
                    IFNULL(CONCAT(' ', param_name3), ''),
                    IFNULL(CONCAT(' ', param_name4), '')
                )
            ), ' ', ', '
        )
    ) as 'Parameter(s)'
FROM pools ORDER BY pool_name;

You may also find the following stored procedure useful. It returns a list of pools associated with a given configuration parameter, along with the kernel blocks to which these pools belong. You can see here the statement used to create this stored procedure along with sample output for some typical parameters:

mysql> DELIMITER |
mysql> CREATE PROCEDURE get_pools (p VARCHAR(50))
    -> BEGIN
    ->     SELECT 
    ->         DISTINCT(pool_name) as Pool,
    ->         block_name as Block
    ->     FROM ndbinfo.pools
    ->     WHERE p
    ->           IN (param_name1, param_name2, param_name3, param_name4)
    .>     ORDER BY Pool;
    -> END
    -> |
Query OK, 0 rows affected (0.02 sec)

mysql> DELIMITER ;

mysql> CALL get_pools('MaxNoOfTables');
+-----------------+------------+
| pool_name       | block_name |
+-----------------+------------+
| Table Record    | DBDICT     |
| DictObject      | DBDICT     |
| Index           | DBTC       |
| Table           | BACKUP     |
| Trigger         | BACKUP     |
| Fragment        | BACKUP     |
| Subscriber      | SUMA       |
| Table           | SUMA       |
| Subscription    | SUMA       |
| Index           | DBTUX      |
| Descriptor page | DBTUX      |
+-----------------+------------+
11 rows in set (0.30 sec)

Query OK, 0 rows affected (0.30 sec)

mysql> CALL get_pools('MaxNoOfOrderedIndexes');
+-----------------+------------+
| pool_name       | block_name |
+-----------------+------------+
| DictObject      | DBDICT     |
| Index           | DBTC       |
| Table           | BACKUP     |
| Trigger         | BACKUP     |
| Fragment        | BACKUP     |
| Index           | DBTUX      |
| Fragment        | DBTUX      |
| Descriptor page | DBTUX      |
+-----------------+------------+
8 rows in set (0.29 sec)