从Mongo获取多个查询

Question

在NodeJS中，有没有更好/更优的方法从Mongo中获取多个查询？我为每个用户循环运行这段代码，所以当我的用户群增长时，我担心这段代码的性能和可靠性。

const cron = require('node-cron');
cron.schedule(process.env.SCHEDULE_TIME, async () => calculateUserHonors(), {
  scheduled: true,
  timezone: 'Europe/Prague',
});

const calculateUserHonors = async () => {
 // for loop for every user in database
let pollVotesCount, commentVotesCount, sharesCount, commentsCount, blogCount;
const pollVotesPromise = getPollVoteCount(dbClient, userId);
const commentVotesPromise = getCommentVotesCount(dbClient, userId);
const sharesPromise = getShareLinkCount(dbClient, userId);
const commentsPromise = getCommentedCount(dbClient, userId);
const blogPromise = getBlogCount(dbClient, userId);
Promise.all([pollVotesPromise, commentVotesPromise, sharesPromise, commentsPromise, blogPromise]).then((values) => {
  pollVotesCount = values[0];
  commentVotesCount = values[1];
  sharesCount = values[2];
  commentsCount = values[3];
  blogCount = values[4];
});

const getPollVoteCount = async (dbClient, userId) => dbClient.db().collection('poll_votes').find({ user: userId }).count();

const getCommentVotesCount = async (dbClient, userId) => dbClient.db().collection('comment_votes').find({ 'user.id': userId }).count();

const getShareLinkCount = async (dbClient, userId) => dbClient.db().collection('link_shares').find({ user: userId }).count();

const getCommentedCount = async (dbClient, userId) => dbClient.db().collection('comments').find({ 'user.id': userId }).count();

const getBlogCount = async (dbClient, userId) => dbClient.db().collection('items').find({ 'info.author.id': userId }).count();

Answer 1

您应该查看聚合管道：https://docs.mongodb.com/manual/reference/operator/aggregation-pipeline/

例如，要获取poll_votes

dbClient.db().collection('poll_votes').aggregate([
    { $group: { _id: '$user', count: { $sum: 1 } } },
    { $addFields: { user: '$_id', pollVotes: '$count' } }
]);

您将获得一个包含每个用户的投票结果的数组。