diff --git a/README.md b/README.md
index 033c90a..1f0dc05 100644
--- a/README.md
+++ b/README.md
@@ -408,6 +408,24 @@ INSERT INTO `user` SET `name` = 'fengmk2', `createdAt` = now()
 const session = new db.literals.Literal('session()');
 ```
 
+## Class Relation
+
+```txt
++-----------+                          +----------------+
+| RDSClient +-- beginTransaction() --> + RDSTransaction |
++--+----+---+                          +----+----+------+
+   |    | getConnection()            .conn  |    |
+   |    |         +---------------+         |    |
+   |    +-------->+ RDSConnection +<--------+    |
+   |              +-------+-------+              |
+   |                      | extends              |
+   |                      v                      |
+   |   extends    +-------+-------+    extends   |
+   +------------->+   Operator    +<-------------+
+                  |    query()    |
+                  +---------------+
+```
+
 ## License
 
 [MIT](LICENSE)
diff --git a/src/operator.ts b/src/operator.ts
index f5110b0..d86a5f3 100644
--- a/src/operator.ts
+++ b/src/operator.ts
@@ -79,7 +79,7 @@ export abstract class Operator {
         }
       }
     }
-    debug('query %o', sql);
+    debug('[connection#%s] query %o', this.threadId, sql);
     const queryStart = performance.now();
     let rows: any;
     let lastError: Error | undefined;
@@ -90,15 +90,15 @@ export abstract class Operator {
     try {
       rows = await this._query(sql);
       if (Array.isArray(rows)) {
-        debug('query get %o rows', rows.length);
+        debug('[connection#%s] query get %o rows', this.threadId, rows.length);
       } else {
-        debug('query result: %o', rows);
+        debug('[connection#%s] query result: %o', this.threadId, rows);
       }
       return rows;
     } catch (err) {
       lastError = err;
       err.stack = `${err.stack}\n    sql: ${sql}`;
-      debug('query error: %o', err);
+      debug('[connection#%s] query error: %o', this.threadId, err);
       throw err;
     } finally {
       const duration = Math.floor((performance.now() - queryStart) * 1000) / 1000;
diff --git a/test/PoolConfig.test.ts b/test/PoolConfig.test.ts
index 551e0ee..f82e848 100644
--- a/test/PoolConfig.test.ts
+++ b/test/PoolConfig.test.ts
@@ -81,7 +81,7 @@ describe('test/PoolConfig.test.ts', () => {
     it('should get connection config from newConnectionConfig()', async () => {
       assert.equal(db.pool.config.connectionConfig.database, undefined);
       assert.equal(index, 1);
-      assert.equal((db.pool.config as any).newConnectionConfig().database, 'test');
+      assert.equal((db.pool.config as any).newConnectionConfig().database, config.database);
       assert.equal(index, 2);
     });
 
diff --git a/test/config.ts b/test/config.ts
index 71e07eb..79a2b93 100644
--- a/test/config.ts
+++ b/test/config.ts
@@ -1,13 +1,7 @@
 export default {
-  // host: 'localhost',
-  host: '127.0.0.1',
-  port: 3306,
-  user: 'root',
-  password: '',
-  database: 'test',
-  // host: env.ALI_SDK_RDS_HOST || 'localhost',
-  // port: env.ALI_SDK_RDS_PORT || 3306,
-  // user: env.ALI_SDK_RDS_USER || 'root',
-  // password: env.ALI_SDK_RDS_PASSWORD || '',
-  // database: env.ALI_SDK_RDS_DATABASE || 'test',
+  host: process.env.TEST_ALI_RDS_HOST || '127.0.0.1',
+  port: parseInt(process.env.TEST_ALI_RDS_PORT || '3306'),
+  user: process.env.TEST_ALI_RDS_USER || 'root',
+  password: process.env.TEST_ALI_RDS_PASSWORD || '',
+  database: process.env.TEST_ALI_RDS_DATABASE || 'test',
 };