GO并发相关

锁的使用

注意要成对，重点是代码中有分支或者异常返回的情况，这种情况要在异常返回前先释放锁

    mysqlInstanceLock.Lock()
    slaveHostSql := "show slave hosts"
    ss1 := dc.SqlRes(DcServer, ip, port, msdb.DbName, slaveHostSql,false , common.AdminMysqlUserName, common.AdminMysqlPassword)

    if ss1 == "" {  //has not slave hosts;
        mysqlInstanceLock.Unlock()
        return
    }

    mysqlInstanceLock.Unlock()