问题描述
解决方法
此基准代码表明 Post.find({ owner: user_id })
的速度要快一些。
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
const NUM_USERS = 100;
const NUM_POSTS_PER_USER = 10;
mongoose.connect('mongodb://localhost:27017/testdb',{ useNewUrlParser: true });
const userSchema = Schema({
posts: [{ type: Schema.Types.ObjectId,ref: 'Post' }]
});
const postSchema = Schema({
owner: { type: Schema.Types.ObjectId,ref: 'User' },title: String,content: String,});
const User = mongoose.model('User',userSchema);
const Post = mongoose.model('Post',postSchema);
const userIds = [];
async function seed() {
await User.deleteMany({});
await Post.deleteMany({});
for (let i = 0; i < NUM_USERS; ++i) {
const user = new User();
await user.save();
for (let i = 0; i < NUM_POSTS_PER_USER; ++i) {
const post = new Post({
owner: user,title: Array(50).fill('a').join(''),content: Array(1000).fill('b').join(''),});
await post.save();
user.posts.push(post);
}
await user.save();
userIds.push(user._id);
}
}
async function benchmarkPopulate() {
console.time('populate');
for (const id of userIds) {
await User.findOne({ _id: id }).populate("posts");
}
console.timeEnd('populate');
}
async function benchmarkFind() {
console.time('find');
for (const user_id of userIds) {
await Post.find({ owner: user_id });
}
console.timeEnd('find');
}
async function main() {
await seed();
await benchmarkPopulate();
await benchmarkFind();
await benchmarkPopulate();
await benchmarkFind();
await mongoose.disconnect();
}
main();
输出:
populate: 217.534ms
find: 121.905ms
populate: 169.181ms
find: 120.171ms
这并不奇怪,因为 Post.find({ owner: user_id })
只需要查询一个集合。
这些结果在各次运行中相当一致(即使您颠倒了基准测试的顺序)。
您的里程可能会有所不同,这种差异并不重要,尤其是当您通过网络查询数据库时。