云数据库接口调用警告调用时间超过3秒怎么解决？

代码很简单，没有复杂的查询，但是仍旧报调用时间超过3秒的告警。运行环境是云函数。

Database operation database.queryDocument is longer than 3s. Please check query performance and your network environment.

async function getHelpMark(result) {   console.log("qzid:" + result.qzid)   return new Promise(function(resolve, reject) {     let db = cloud.database()     let t_quizzes = db.collection('quizzes')     t_quizzes.doc(result.qzid)       .field({ helpMark: true })       .get().then(res => {         console.log(res)         resolve({           qzid: result.qzid,           helpMark: res.data.helpMark       })     })   }) }

看不出有什么影响效率的地方，请高手指点迷津，谢谢！