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| # 配置项修改介绍 |
| ## 设置方式 |
| * 使用sql语句修改【推荐】 |
| * 直接修改配置文件【不推荐】 |
| ## 生效方式 |
| * 第一次启动后不可修改 (first_start) |
| * 重启后生效 (restart) |
| * 热加载 (hot_reload) |
| # 直接修改配置文件 |
| 可以通过重启或以下命令生效 |
| ## 热加载配置命令 |
| 使支持热加载的配置项改动立即生效。 |
| 对于已经写在配置文件中修改过的配置项，从配置文件中删除或注释后再进行 load configuration 将恢复默认值。 |
| ``` |
| load configuration |
| ``` |
| # 配置项操作语句 |
| 设置配置项 |
| ``` |
| set configuration 'key1' = 'value1' 'key2' = 'value2'... (on nodeId) |
| ``` |
| ### 示例1 |
| ``` |
| set configuration 'enable_cross_space_compaction' = 'false' |
| ``` |
| 对集群所有节点永久生效，设置 enable_cross_space_compaction 为 false，并写入到 iotdb-system.properties 中。 |
| ### 示例2 |
| ``` |
| set configuration 'enable_cross_space_compaction' ='false' 'enable_seq_space_compaction' = 'false' on 1 |
| ``` |
| 对 nodeId 为 1 的节点永久生效，设置 enable_cross_space_compaction 为 false，设置 enable_seq_space_compaction 为 false，并写入到 iotdb-system.properties 中。 |
| ### 示例3 |
| ``` |
| set configuration 'enable_cross_space_compaction' = 'false' 'timestamp_precision' = 'ns' |
| ``` |
| 对集群所有节点永久生效，设置 enable_cross_space_compaction 为 false，timestamp_precision 为 ns，并写入到 iotdb-system.properties 中。但是，timestamp_precision 是第一次启动后就无法修改的配置项，因此会忽略这个配置项的更新，返回如下。 |
| ``` |
| Msg: org.apache.iotdb.jdbc.IoTDBSQLException: 301: ignored config items: [timestamp_precision] |
| ``` |
| # 生效配置项 |
| 支持热加载立即生效的配置项在 iotdb-system.properties.template 文件中标记 effectiveMode 为 hot_reload |
| 示例 |
| ``` |
| # Used for indicate cluster name and distinguish different cluster. |
| # If you need to modify the cluster name, it's recommended to use [set configuration 'cluster_name'='xxx'] sql. |
| # Manually modifying configuration file is not recommended, which may cause node restart fail. |
| # effectiveMode: hot_reload |
| # Datatype: string |
| cluster_name=defaultCluster |
| ``` |
