Firebase Warning: Using An Unspecified Index When Search Data With Firebase Cloud Function

I built a Firebase Cloud Function that looks for users who has value of 'IsNotificationEnabled' equal to true . Part of my Function export const sendPushNotification = functions.ht

Solution 1:

As the message says, you'll need to add the index to /Users. You're now adding it one level lower, where it won't work.

{"rules":{"Users":{".indexOn":["IsNotificationEnabled"]},".read":true,".write":true}}

I find it easiest to remember where to define an index by thinking of where I run my query. Since your query runs on /Users, you need to define your index on that level.

I also remove your .read and .write rules on /Users/$uid, since they are ineffective. You're granting full read/write access at the root already, and permission cannot be taken away at a lower level.