diff --git a/isolated/.env.example b/isolated/.env.example
index 8bbd4bf..2a51fc0 100644
--- a/isolated/.env.example
+++ b/isolated/.env.example
@@ -55,6 +55,10 @@ MYSQL_ROOT_PASSWORD=change-me-mysql-root
 DB_URL=jdbc:mysql://mysql:3306/emp?useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai
 DB_USER=root
 DB_PWD=change-me-mysql-root
+# Optional read datasource for emp-monitor. Omit to reuse DB_URL.
+# DB_READ_URL=jdbc:mysql://mysql-read:3306/emp?useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai
+# DB_READ_USER=root
+# DB_READ_PWD=change-me-mysql-root
 
 # 给 emp_ws 模拟器读取车辆档案使用。
 SIMULATOR_DB_HOST=mysql
diff --git a/isolated/test/env.txt b/isolated/test/env.txt
index 531b005..ef51cb2 100644
--- a/isolated/test/env.txt
+++ b/isolated/test/env.txt
@@ -55,6 +55,10 @@ MYSQL_ROOT_PASSWORD=emp_2026_06_01_pwd
 DB_URL=jdbc:mysql://mysql:3306/emp?useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai
 DB_USER=root
 DB_PWD=emp_2026_06_01_pwd
+# Optional read datasource for emp-monitor. Omit to reuse DB_URL.
+# DB_READ_URL=jdbc:mysql://mysql-read:3306/emp?useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai
+# DB_READ_USER=root
+# DB_READ_PWD=emp_2026_06_01_pwd
 
 # 给 emp_ws 模拟器读取车辆档案使用。
 SIMULATOR_DB_HOST=mysql