According to Firebase Performance Monitoring Documentation,
Known issues include:
Performance Monitoring has known compatibility issues with GTMSQLite. We recommend not using Performance Monitoring with apps that use GTMSQLite.
Which among the tools are using GTMSQLite? Is there a list somewhere in the documentation?
Knowing these tools will greatly help to avoid unexpected issues while using Firebase Performance Monitoring. Thanks!
No other Firebase SDKs use GTMSQLite. The warning is for either the developer's own usage of or other dependencies outside of Firebase which use GTMSQLite.
The issue is primarily the result of GTMSQLite inability to be made into a cocoapod (see https://github.com/google/google-toolbox-for-mac/blob/b3f485cab2c80a9e685205135d6a63299fe3c394/GoogleToolboxForMac.podspec#L89).
It's not a commonly used library and if there are issues, you'll generally end up with linker errors (symbol collisions).
We're evaluating eliminating this dependency in future versions...