How to bufferize efficiently in nodeJS on events from a stream to bulk insert instead of unique insert per record received from the stream. Here’s pseudo code I’ve got in mind:
// Open MongoDB connection
mystream.on('data', (record) => {
// bufferize data into an array
// if the buffer is full (1000 records)
// bulk insert into MongoDB and empty buffer
})
mystream.on('end', () => {
// close connection
})
Does this look realistic? Is there any possible optimization? Existing libraries facilitaties that?
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Answer
I ended up with a no dependency solution.
const { MongoClient } = require("mongodb")
const url = process.env.MONGO_URI || "mongodb://localhost:27019";
const connection = MongoClient.connect(url, { useNewUrlParser: true, useUnifiedTopology: true })
Promise.resolve(connection)
.then((db) => {
const dbName = "databaseName";
const collection = 'collection';
const dbo = db.db(dbName);
let buffer = []
stream.on("data", (row: any) => {
buffer.push(row)
if (buffer.length > 10000) {
dbo.collection(collection).insertMany(buffer, {ordered: false});
buffer = []
}
});
stream.on("end", () => {
// insert last chunk
dbo.collection(collection).insertMany(buffer, {ordered: false})
.then(() => {
console.log("Done!");
db.close();
})
});
stream.on("error", (err) => console.log(err));
})
.catch((err) => {
console.log(err)
})