Firestore Enterprise (MongoDB Compatibility) — Collections Sync But No Fields/Data
Metabase Version: Cloud (latest)
Database: Google Firestore Enterprise Edition with MongoDB Compatibility (GA since Aug 2025)
Connection Method: MongoDB driver via connection string
The Problem
I've connected my Firestore Enterprise database (which provides native MongoDB API compatibility) to Metabase using the MongoDB driver. The connection succeeds — Metabase discovers all my collections and the sync completes with initial_sync_status: "complete". However, every collection shows zero fields (fields: []), and any attempt to query a table returns:
Table 'conversations' has no Fields associated with it.
Root Cause
After digging through the logs, I found the actual error:
Command execution failed on MongoDB server with error 2 (InvalidArgument):
'1200000 is out of range [0, 60000] for maxTimeMS'
Firestore's MongoDB compatibility layer enforces a maximum maxTimeMS of 60,000ms (60 seconds). Metabase's MongoDB driver sends maxTimeMS: 1200000 (20 minutes) during field introspection, which Firestore rejects. This causes the field discovery step to fail silently — collections appear but with no fields, making the database unusable.
What I've Tried
- Adding
maxTimeMS=55000to the connection string — Metabase ignores this and still sends 1200000 at the operation level - Re-syncing and re-scanning multiple times — same result every time
- Native queries — still same error
Potential Fix
I'm aware that MB_DB_QUERY_TIMEOUT_MINUTES was introduced in v0.49.23 (PR #44759) to make the query timeout configurable. Setting this to 1 minute would bring maxTimeMS to 60,000ms, which is within Firestore's limit. However:
- I'm on Metabase Cloud, so I can't set environment variables myself
- This is a global setting — it would affect all connected databases, not just Firestore
Ideally, the MongoDB driver should either:
- Respect a per-database timeout setting
- Or cap
maxTimeMSbased on the server's reported limits
Questions for the Community/Team
- Is there a way to set
MB_DB_QUERY_TIMEOUT_MINUTESon Metabase Cloud? - Is there any per-database timeout override for the MongoDB driver?
- Has anyone else successfully connected Firestore Enterprise (MongoDB mode) to Metabase?
Any help would be appreciated. Firestore Enterprise with MongoDB compatibility is becoming increasingly popular, so this is likely an issue more users will hit as adoption grows.