DBLE Server.xml Configuration Guide: System, User, and Firewall Settings

DBLE is an enterprise‑grade open‑source distributed middleware derived from MyCat, designed for high‑concurrency and TB‑scale data processing. The article introduces its official website, GitHub project, download links, and community group.

The main configuration files reside in the conf directory, with server.xml, schema.xml, and rule.xml being the most frequently used.

DBLE uses conf/wrapper.conf to manage JVM settings; detailed documentation is available at the provided URL.

Server.xml Configuration

Server.xml is divided into three sections: <system>, <user>, and <firewall>. The <system> section defines performance, scheduled tasks, ports, and user parameters. A sample XML snippet is shown:

<dble:server>
  <system></system>
  <user></user>
  <firewall>
    <whitehost></whitehost>
  </firewall>
</dble:server>

To apply configuration changes at runtime, the reload @@config command can be used, but changes in the <system> block require a full restart.

System Parameters

property

作用

serverPort

业务用户连接端口

managerPort

管理用户连接端口

charset

字符集

maxCon

控制最大连接数

processors

NIO前端处理器的数量，默认java虚拟机核数

enableSlowLog

是否允许慢查询，默认不开启

sqlSlowTime

慢查询阈值（毫秒）

User Configuration

Users are defined inside the <user> block. Each user can be bound to one or multiple schemas, and fine‑grained DML permissions can be set via the privileges element. Example user definitions:

<user name="adv_user">
  <property name="password">adv_user</property>
  <property name="schemas">adv</property>
  <property name="readOnly">false</property>
</user>
<user name="motor_user">
  <property name="password">motor_user</property>
  <property name="schemas">motor</property>
  <property name="readOnly">false</property>
</user>

For a user needing access to multiple schemas, the schemas attribute can list them separated by commas, e.g., adv_motor_user with schemas="motor,adv".

DML permissions are expressed as a four‑digit binary string (INSERT, UPDATE, SELECT, DELETE). The example below grants full DML rights on all tables of schema adv and overrides table tb01 to allow all four operations:

<user name="adv_user">
  ...
  <privileges check="true">
    <schema name="adv" dml="1110">
      <table name="tb01" dml="1111"/>
    </schema>
  </privileges>
</user>

Blacklist / Whitelist (Firewall)

DBLE provides a firewall with whitehost (allow list) and blacklist (fine‑grained deny rules). The whitelist restricts connections by IP and username; the blacklist can further limit SQL actions such as SELECT, INSERT, UPDATE, etc.

<firewall>
  <whitehost>
    <host host="127.0.0.1" user="adv_user"/>
    <host host="127.0.0.1" user="admin"/>
  </whitehost>
  <blacklist check="true">
    <property name="selectAllow">false</property>
    <property name="insertAllow">false</property>
    <property name="updateAllow">false</property>
    ...
  </blacklist>
</firewall>

The article concludes that DBLE’s Server.xml offers system settings, user management with schema‑level and table‑level privileges, and a powerful blacklist/whitelist mechanism for precise access control.