diff --git a/dbpool.go b/dbpool.go
index 848390f..d7404f7 100644
--- a/dbpool.go
+++ b/dbpool.go
@@ -2,6 +2,7 @@ package f5
 
 import (
 	"q5"
+	"time"
 	"fmt"
 	"math"
 	"strings"
@@ -16,6 +17,7 @@ const (
 )
 
 type dataSource struct {
+	name string
 	conn *q5.Mysql
 	entry q5.ListHead
 }
@@ -45,6 +47,7 @@ func (this *dbPool) RegisterDataSource(name string, host string, port int32,
 	}
 	for i := int32(0); i < size; i++ {
 		ds := dataSource{}
+		ds.name = name
 		ds.conn = q5.NewMysql(host, port, user, passwd, dataBase)
 		ds.entry.Init(&ds)
 		head.AddTail(&ds.entry)
@@ -182,16 +185,35 @@ func (this *dbPool) PageQuery(
 		})
 }
 
-func (this *dbPool) borrowConn(dataSource string) *dataSource {
-	this.lock.Lock()
-	defer this.lock.Unlock()
-
+func (this *dbPool) borrowConn(name string) *dataSource {
+	tryCount := 0
+	for tryCount < 5 {
+		{
+			this.lock.Lock()
+			defer this.lock.Unlock()
+			if head, ok := this.dataSourceHash[name]; ok {
+				if !head.Empty() {
+					next := head.Next()
+					next.Del()
+					return next.GetData().(*dataSource)
+				}
+			}
+		}
+		time.Sleep(time.Second * 1)
+		tryCount++
+	}
 	return nil
 }
 
 func (this *dbPool) returnConn(ds *dataSource) {
 	this.lock.Lock()
 	defer this.lock.Unlock()
+
+	if head, ok := this.dataSourceHash[ds.name]; ok {
+		head.AddTail(&ds.entry)
+	} else {
+		panic(fmt.Sprintf("returnConn error %s", ds.name))
+	}
 }
 
 func (this *dbPool) joinSelectFields(fields []string) string {