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25.6.17.12 ndbinfo config_values 表

config_values提供了节点配置参数当前状态的信息。每一行对应于某个节点上的当前参数值。

config_values包含以下列:

  • node_id

    集群中的节点ID

  • config_param

    参数的内部ID号

  • config_value

    参数当前值

该表的config_param列和config_params表的param_number列使用相同的参数标识符。通过将这两个表连接在这些列上,您可以获得关于所需节点配置参数的详细信息。以下查询提供了每个数据节点在集群中的当前值,按节点ID和参数名称排序:

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;

从前一个查询中部分输出结果,当在用于简单测试的小型示例集群上运行时:

+---------+------------------------------------------+----------------+
| 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)

WHERE子句过滤掉以双下划线(__)开头的参数名称,这些参数是NDB开发者保留的,用于测试和其他内部使用,不适合在生产环境中使用NDB集群。

可以通过发出适当的查询来获得更具体、更详细或两者的输出。这一例子提供了当前对所有数据节点在集群中的NodeIdNoOfReplicasHostNameDataMemoryIndexMemoryTotalSendBufferMemory参数的所有类型信息。

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

在运行于小型 NDB 集群(用于简单测试)的数据节点 2 个时,这个查询的输出结果如下所示:

*************************** 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)