We have dynamic pages being served by Firebase Cloud Functions, but the TTFB is very slow on these pages with TTFB of 900ms - 2s, at first we just assumed it to be a cold start issue, but even with consistent traffic it is very slow at TTFB of 700ms - 1.2s.
This is a bit problematic for our project since it is organic traffic dependent and Google Pagespeed would need a server response of less than 200ms.
Anyway, we tried to check what might be causing the issue and we pinpointed it with Firestore, when a Cloud Function accesses Firestore, we noticed there are some delays. This is a basic sample code of how we implement Cloud Function and Firestore:
dynamicPages.get('/ph/test/:id', (req, res) => {
var globalStartTime = Date.now();
var period = [];
db.collection("CollectionTest")
.get()
.then((querySnapshot) => {
period.push(Date.now() - globalStartTime);
console.log('1', period);
return db.collection("CollectionTest")
.get();
})
.then((querySnapshot) => {
period.push(Date.now() - globalStartTime);
console.log('2', period);
res.status(200)
.send('Period: ' + JSON.stringify(period));
return true;
})
.catch((error) => {
console.log(error);
res.end();
return false;
});
});
This is running on Firebase + Cloud Functions + NodeJS
CollectionTest is very small with only 100 documents inside, with each document having the following fields:
directorName: (string)
directorProfileUrl: (string)
duration: (string)
genre: (array)
posterUrl: (string)
rating: (string)
releaseDate: (string)
status: (int)
synopsis: (string)
title: (string)
trailerId: (string)
urlId: (string)
With this test, we would get the following results:
[467,762] 1.52s
[203,315] 1.09s
[203,502] 1.15s
[191,297] 1.00s
[206,319] 1.03s
[161,267] 1.03s
[115,222] 843ms
[192,301] 940ms
[201,308] 945ms
[208,312] 950ms
This data is [Firestore Call 1 Exectution Time, Firestore Call 2 Exectution Time] TTFB
If we check the results of the test, there are signs that the TTFB is getting lower, maybe that is when the Cloud Function has already warmed up? But even so, Firestore is eating up 200-300ms in the Cloud Function based on the results of our second Firestore Call and even if Firestore took lesser time to execute, TTFB would still take up 600-800ms, but that is a different story.
Anyway, can anyone help how we can improve Firestore performance in our Cloud Functions (or if possible, the TTFB performance)? Maybe we are doing something obviously wrong that we don't know about?
