feature request: support index manager APIs for firestore

[joaqo]

Hi, I was just wondering if there is documentation for the Index Manager introduced around September 2023 in the official SDK?

@mikehardy I saw you commenting on their original PR, so I am assuming it got implemented here as well?

Thanks!

[mikehardy]

Hey @joaqo - I investigated that one but never got a reply on that query, so I did not complete any implementation work here - it has sat idle sense then

Documented above now - just not with the capital P - https://firebase.google.com/docs/reference/ios/firebasefirestore/api/reference/Classes/FIRFirestore#persistentcacheindexmanager

So, nothing blocking implementation here as it exists on web (for API shape) and android+ios (for underlying implementation)

Does not exist here as an implementation yet though - I'll leave this open with a slightly altered title, and would happily collaborate on getting a PR in that implemented it

[joaqo]

Hi @mikehardy, been looking into the issue a bit, and it seems the Firebase team is converging towards a really simple API for this. From their docs:

NOTE: This preview method will be deprecated in a future major release. Consider using PersistentCacheIndexManager.enableIndexAutoCreation() to let the SDK decide whether to create cache indexes for queries running locally.

So it seems like it would just be exposing a boolean to turn on/off the auto index creation, at least to get the basic feature running.

I tried to make it work but I'm failing hard without any Objective-C knowledge, little knowledge about React Native's backend, and no familiarity with how RNFB works behind the scenes. Following their docs, this is what I have tried adding to RNFBFirestore/RNFBFirestoreCommon.m:

• Add to imports:

#import <FirebaseFirestoreInternal/FIRPersistentCacheIndexManager.h>

• Add to (void)setFirestoreSettings:(FIRFirestore *)firestore appName: right after firestore.settings = firestoreSettings;:

    FIRPersistentCacheIndexManager *indexManager = [FIRFirestore firestore].persistentCacheIndexManager;
    if (indexManager) {
        // Indexing is disabled by default
        [indexManager enableIndexAutoCreation];
    }

My app runs with this code just fine, but I'm not seeing any difference in performance. Just wanted to share this with you in case this is something trivial for you to implement, as I've been struggling with it myself quite a bit.

Thanks!