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21.6.15.9 The ndbinfo config_values Table

The config_values table, implemented in NDB 7.5.0, provides information about the current state of node configuration parameter values. Each row in the table corresponds to the current value of a parameter on a given node.

  • node_id

    ID of the node in the cluster

  • config_param

    The parameter's internal ID number

  • config_value

    Current value of the parameter

Notes

This table's config_param column and the config_params table's param_number column use the same parameter identifiers. By joining the two tables on these columns, you can obtain detailed information about desired node configuration parameters. The query shown here provides the current values for all parameters on each data node in the cluster, ordered by node ID and parameter name:

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SELECT v.node_id AS 'Node Id', p.param_name AS 'Parameter', v.config_value AS 'Value' FROM config_values v JOIN config_params p ON v.config_param=p.param_number WHERE p.param_name NOT LIKE '\_\_%' ORDER BY v.node_id, p.param_name;

Partial output from the previous query when run on a small example cluster used for simple testing:

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+---------+------------------------------------------+----------------+ | Node Id | Parameter | Value | +---------+------------------------------------------+----------------+ | 2 | Arbitration | 1 | | 2 | ArbitrationTimeout | 7500 | | 2 | BackupDataBufferSize | 16777216 | | 2 | BackupDataDir | /home/jon/data | | 2 | BackupDiskWriteSpeedPct | 50 | | 2 | BackupLogBufferSize | 16777216 | ... | 3 | TotalSendBufferMemory | 0 | | 3 | TransactionBufferMemory | 1048576 | | 3 | TransactionDeadlockDetectionTimeout | 1200 | | 3 | TransactionInactiveTimeout | 4294967039 | | 3 | TwoPassInitialNodeRestartCopy | 0 | | 3 | UndoDataBuffer | 16777216 | | 3 | UndoIndexBuffer | 2097152 | +---------+------------------------------------------+----------------+ 248 rows in set (0.02 sec)

The WHERE clause filters out parameters whose names begin with a double underscore (__); these parameters are reserved for testing and other internal uses by the NDB developers, and are not intended for use in a production NDB Cluster.

You can obtain output that is more specific, more detailed, or both by issuing the proper queries. This example provides all types of available information about the NodeId, NoOfReplicas, HostName, DataMemory, IndexMemory, and TotalSendBufferMemory parameters as currently set for all data nodes in the cluster:

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SELECT p.param_name AS Name, v.node_id AS Node, p.param_type AS Type, p.param_default AS 'Default', p.param_min AS Minimum, p.param_max AS Maximum, CASE p.param_mandatory WHEN 1 THEN 'Y' ELSE 'N' END AS 'Required', v.config_value AS Current FROM config_params p JOIN config_values v ON p.param_number = v.config_param WHERE p. param_name IN ('NodeId', 'NoOfReplicas', 'HostName', 'DataMemory', 'IndexMemory', 'TotalSendBufferMemory')\G

The output from this query when run on a small NDB Cluster with 2 data nodes used for simple testing is shown here:

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*************************** 1. row *************************** Name: NodeId Node: 2 Type: unsigned Default: Minimum: 1 Maximum: 48 Required: Y Current: 2 *************************** 2. row *************************** Name: HostName Node: 2 Type: string Default: localhost Minimum: Maximum: Required: N Current: 127.0.0.1 *************************** 3. row *************************** Name: TotalSendBufferMemory Node: 2 Type: unsigned Default: 0 Minimum: 262144 Maximum: 4294967039 Required: N Current: 0 *************************** 4. row *************************** Name: NoOfReplicas Node: 2 Type: unsigned Default: 2 Minimum: 1 Maximum: 4 Required: N Current: 2 *************************** 5. row *************************** Name: DataMemory Node: 2 Type: unsigned Default: 102760448 Minimum: 1048576 Maximum: 1099511627776 Required: N Current: 524288000 *************************** 6. row *************************** Name: NodeId Node: 3 Type: unsigned Default: Minimum: 1 Maximum: 48 Required: Y Current: 3 *************************** 7. row *************************** Name: HostName Node: 3 Type: string Default: localhost Minimum: Maximum: Required: N Current: 127.0.0.1 *************************** 8. row *************************** Name: TotalSendBufferMemory Node: 3 Type: unsigned Default: 0 Minimum: 262144 Maximum: 4294967039 Required: N Current: 0 *************************** 9. row *************************** Name: NoOfReplicas Node: 3 Type: unsigned Default: 2 Minimum: 1 Maximum: 4 Required: N Current: 2 *************************** 10. row *************************** Name: DataMemory Node: 3 Type: unsigned Default: 102760448 Minimum: 1048576 Maximum: 1099511627776 Required: N Current: 524288000 10 rows in set (0.01 sec)