用go 链接MySQL 用ab 压测报错误

这是报错： 2016/06/16 07:20:29 http: panic serving 127.0.0.1:55356: sql: database is closed goroutine 1789 [running]: net/http.(conn).serve.func1(0xc82157e200) /usr/local/go/src/net/http/server.go:1389 +0xc1 main.checkErr(0x6b4028, 0xc82000aed0) /data/go/src/basis/main.go:86 +0x4b main.(sqlOpen).mysqlSelect(0xc820028020, 0x1201078, 0xc820060680, 0xc821828540) /data/go/src/basis/main.go:38 +0xdd main.(sqlOpen).(main.mysqlSelect)-fm(0x1201078, 0xc820060680, 0xc821828540) /data/go/src/basis/main.go:93 +0x3e net/http.HandlerFunc.ServeHTTP(0xc82000b000, 0x1201078, 0xc820060680, 0xc821828540) /usr/local/go/src/net/http/server.go:1618 +0x3a net/http.(ServeMux).ServeHTTP(0xc820014ab0, 0x1201078, 0xc820060680, 0xc821828540) /usr/local/go/src/net/http/server.go:1910 +0x17d net/http.serverHandler.ServeHTTP(0xc820066080, 0x1201078, 0xc820060680, 0xc821828540) /usr/local/go/src/net/http/server.go:2081 +0x19e net/http.(conn).serve(0xc82157e200) /usr/local/go/src/net/http/server.go:1472 +0xf2e created by net/http.(Server).Serve /usr/local/go/src/net/http/server.go:2137 +0x44e

这是我的链接数据库:

database , err := sql.Open( "mysql" , "admin:admin@tcp(192.168.200.101:3306)/test_database?charset=utf8" )
    if err != nil {
        checkErr( err )
    }
    s.db = database
    return

本人刚开始学习不知道问题是什么，初步怀疑是因为连接数大照成的。不知道正确不正确，求牛人指点一二谢谢