diff --git a/src/main/java/com/alibaba/druid/pool/DruidAbstractDataSource.java b/src/main/java/com/alibaba/druid/pool/DruidAbstractDataSource.java
index 07b32a8ad2..a94077b7bf 100644
--- a/src/main/java/com/alibaba/druid/pool/DruidAbstractDataSource.java
+++ b/src/main/java/com/alibaba/druid/pool/DruidAbstractDataSource.java
@@ -493,6 +493,10 @@ public abstract class DruidAbstractDataSource extends WrapperAdapter implements
     public String getDbType() {
         return dbType;
     }
+    
+    public void setDbType(String dbType) {
+        this.dbType = dbType;
+    }
 
     public void addConnectionProperty(String name, String value) {
         if (inited) {
diff --git a/src/main/java/com/alibaba/druid/pool/DruidDataSource.java b/src/main/java/com/alibaba/druid/pool/DruidDataSource.java
index e3e00bf0ea..24a144ec1b 100644
--- a/src/main/java/com/alibaba/druid/pool/DruidDataSource.java
+++ b/src/main/java/com/alibaba/druid/pool/DruidDataSource.java
@@ -291,8 +291,10 @@ public class DruidDataSource extends DruidAbstractDataSource implements DruidDat
                 }
             }
 
-            this.dbType = JdbcUtils.getDbType(jdbcUrl, driverClass.getClass().getName());
-
+            if (this.dbType == null || this.dbType.length() == 0) {
+                this.dbType = JdbcUtils.getDbType(jdbcUrl, driverClass.getClass().getName());
+            }
+            
             if ("oracle".equals(this.dbType)) {
                 isOracle = true;
 
diff --git a/src/main/java/com/alibaba/druid/wall/WallFilter.java b/src/main/java/com/alibaba/druid/wall/WallFilter.java
index 317baff139..abad1d349e 100644
--- a/src/main/java/com/alibaba/druid/wall/WallFilter.java
+++ b/src/main/java/com/alibaba/druid/wall/WallFilter.java
@@ -40,30 +40,28 @@ public class WallFilter extends FilterAdapter implements WallFilterMBean {
     public void init(DataSourceProxy dataSource) {
         this.dataSource = dataSource;
 
-        String dbType = this.dbType;
-
         if (this.dbType == null || this.dbType.trim().length() == 0) {
             this.dbType = dataSource.getDbType();
         }
 
         if (JdbcUtils.MYSQL.equals(dbType)) {
-            provider = new MySqlWallProvider(config);
-
             if (config == null) {
                 config = new WallConfig(MySqlWallProvider.DEFAULT_CONFIG_DIR);
             }
+            
+            provider = new MySqlWallProvider(config);
         } else if (JdbcUtils.ORACLE.equals(dbType)) {
-            provider = new OracleWallProvider(config);
-
             if (config == null) {
                 config = new WallConfig(OracleWallProvider.DEFAULT_CONFIG_DIR);
             }
+            
+            provider = new OracleWallProvider(config);
         } else if (JdbcUtils.SQL_SERVER.equals(dbType)) {
-            provider = new SQLServerProvider(config);
-
             if (config == null) {
                 config = new WallConfig(SQLServerProvider.DEFAULT_CONFIG_DIR);
             }
+            
+            provider = new SQLServerProvider(config);
         } else {
             throw new IllegalStateException("dbType not support : " + dbType);
         }
diff --git a/src/test/java/com/alibaba/druid/pool/TestMockPerf.java b/src/test/java/com/alibaba/druid/pool/TestMockPerf.java
index e651df9f58..2e1918e856 100644
--- a/src/test/java/com/alibaba/druid/pool/TestMockPerf.java
+++ b/src/test/java/com/alibaba/druid/pool/TestMockPerf.java
@@ -1,6 +1,7 @@
 package com.alibaba.druid.pool;
 
 import java.sql.Connection;
+import java.sql.Statement;
 
 import junit.framework.TestCase;
 
@@ -14,6 +15,8 @@ public class TestMockPerf extends TestCase {
         dataSource.setInitialSize(3);
         dataSource.setMinIdle(3);
         dataSource.setMaxActive(20);
+        dataSource.setDbType("mysql");
+        dataSource.setFilters("stat,wall");
         dataSource.init();
     }
 
@@ -29,6 +32,9 @@ public class TestMockPerf extends TestCase {
     public void perf() throws Exception {
         for (int i = 0; i < 1000 * 1000; ++i) {
             Connection conn = dataSource.getConnection();
+            Statement stmt = conn.createStatement();
+            stmt.execute("SELECT 1");
+            stmt.close();
             conn.close();
         }
     }