The config_values
table 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.
The config_values
table contains the
following columns:
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:
Press CTRL+C to copySELECT 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:
Press CTRL+C to copy+---------+------------------------------------------+----------------+ | 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:
Press CTRL+C to copySELECT 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:
Press CTRL+C to copy*************************** 1. row *************************** Name: NodeId Node: 2 Type: unsigned Default: Minimum: 1 Maximum: 144 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: 144 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)