Question:

How to optimize getting multiple documents 'one by one' in Firestore?

Problem:

I'm using Node.js + Firestore. To provide more context, the structure of my database is as follows:

Firestore

|-- card (Collection)

| |-- SCP-002 (Document)

| | |-- name: The "Living" Room

| | |-- file: http://scp-es.com/scp-002

| |

| |-- SCP-003 (Document)

| |-- name: Biological Motherboard

| |-- file: http://scp-es.com/scp-003

|-- obtention (Collection)

|-- 7UHIhguG767F

| |-- user: /user/32138217391

| |-- card: /card/REG-001

|-- KkNJbVCr65TY

|-- user: /user/08498328422

|-- card: /card/REG-002

The fields in the 'obtention' documents are references to documents in the 'cards' collection. Therefore, if I want to access the data of a user's cards (such as the name) e.g for a console list, I do the following:

const userReference = database.collection('user').doc(interaction.user.id);

const cardsReference = database.collection('obtention').where('user', '==', userReference);

const cardsSnapshot = await cardsReference.get();

const cards = [];

for (const x of cardsSnapshot.docs) {

const obtention = x.data();

const cardReference = obtention.card;

const cardDocument = await cardReference.get();

cards.push(cardDocument);

}

// Rest of the code

The code works as expected, but the issue is that it takes a long time to fetch card records, and this delay increases with more data (7 seconds for about 10 records). My question is whether there's a way to speed up this process and reduce the time it takes to obtain the same result?

Solution:

Don't use an await for each individual cardReference.get() call, but gather all of these calls into an array and then pass that to Promise.all.

const promises = [];

for (const x of cardsSnapshot.docs) {

const obtention = x.data();

const cardReference = obtention.card;

promises.push(cardReference.get());

}

const cards = await Promise.all(promises);

>Reading a shapefile from Azure Blob Storage and Azure Databricks

>How to replace a value by another in certain columns of a 3d Numpy array?

>How to fix "segmentation fault" issue when using PyOpenGL on Mac?