OceanBase 数据库的配置项对应 OceanBase 数据库的集群参数，通过配置项可以控制集群的负载均衡、合并时间、合并方式、资源分配和模块开关等。

生效方式

配置项一般分为动态生效和重启生效两种方式，大部分配置项为动态生效方式，即不需要重启 OBServer 即可生效。

参数级别

OceanBase 数据库的配置项分为集群级别和租户级别。

查询某个配置项为集群级别还是租户级别的方法如下：

obclient> SHOW PARAMETERS LIKE 'max_syslog_file_count';
+-------+----------+----------------+----------+-----------------------+-----------+-------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------+---------+---------+-------------------+
| zone  | svr_type | svr_ip         | svr_port | name                  | data_type | value | info
                                                                                                                             | section  | scope   | source  | edit_level        |
+-------+----------+----------------+----------+-----------------------+-----------+-------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------+---------+---------+-------------------+
| zone2 | observer |  
xx.xx.xx.xx 
 |     2882 | max_syslog_file_count | NULL      | 0     | specifies the maximum number of the log files that can co-exist before the log file recycling kicks in. Each log file can occupy at most 256MB disk space. When this value is set to 0, no log file will be removed. Range: [0, +∞) in integer   | OBSERVER | CLUSTER | DEFAULT | DYNAMIC_EFFECTIVE |
| zone2 | observer | xx.xx.xx.xx |     2882 | max_syslog_file_count | NULL      | 0     | specifies the maximum number of the log files that can co-exist before the log file recycling kicks in. Each log file can occupy at most 256MB disk space. When this value is set to 0, no log file will be removed. Range: [0, +∞) in integer   | OBSERVER | CLUSTER | DEFAULT | DYNAMIC_EFFECTIVE |
| zone3 | observer | xx.xx.xx.xx |     2882 | max_syslog_file_count | NULL      | 0     | specifies the maximum number of the log files that can co-exist before the log file recycling kicks in. Each log file can occupy at most 256MB disk space. When this value is set to 0, no log file will be removed. Range: [0, +∞) in integer   | OBSERVER | CLUSTER | DEFAULT | DYNAMIC_EFFECTIVE |
| zone1 | observer | xx.xx.xx.xx |     2882 | max_syslog_file_count | NULL      | 0     | specifies the maximum number of the log files that can co-exist before the log file recycling kicks in. Each log file can occupy at most 256MB disk space. When this value is set to 0, no log file will be removed. Range: [0, +∞) in integer   | OBSERVER | CLUSTER | DEFAULT | DYNAMIC_EFFECTIVE |
| zone1 | observer | xx.xx.xx.xx |     2882 | max_syslog_file_count | NULL      | 0     | specifies the maximum number of the log files that can co-exist before the log file recycling kicks in. Each log file can occupy at most 256MB disk space. When this value is set to 0, no log file will be removed. Range: [0, +∞) in integer   | OBSERVER | CLUSTER | DEFAULT | DYNAMIC_EFFECTIVE |
+-------+----------+----------------+----------+-----------------------+-----------+-------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------+---------+---------+-------------------+
5 rows in set (0.02 sec)

其中，scope 列对应的值为 CLUSTER 表示该配置项为集群级别；如果 scope 列对应的值为 TENANT，则表示该配置项为租户级别。

管理权限

配置项的管理遵循以下管理规则：

• 系统租户可以查看和设置所有其他租户（包括系统租户）的配置项。

• 普通租户只能查看和设置本租户的配置项。

当 OBServer 启动后，如果未指定配置项，则系统会使用指定配置项的默认值。更多配置项的查看和设置操作请参见 集群参数管理 章节。

与系统变量对比