Firebase Analytics event logging error

Question

I use Firebase Analytics and my app logs some events with this code:

Bundle bundle = new Bundle(); bundle.putString(FirebaseAnalytics.Param.ITEM_ID, "SOME_ID") bundle.putString(FirebaseAnalytics.Param.CONTENT_TYPE, "SOME_TYPE"); mFirebaseAnalytics.logEvent(FirebaseAnalytics.Event.SELECT_CONTENT, bundle); 

And it seem to work well most of the time. In logcat I have something like this:

Logging event (FE): select_content, Bundle[{_o=app, content_type=SOME_TYPE, item_id=SOME_ID}] 

But for some events I receive

Logging event (FE): select_content, Bundle[{_o=app, _ev=item_id, _err=4, content_type=SOME_TYPE}] 

Apparently, _err=4 is some kind of error code. What does it mean?

In that cases with error my item_id was a pretty long string (20-30 symbols). Maybe there is a limitation on the length of the item_id?

Answer 1

According to Official Documentation:

Param names can be up to 40 characters long, may only contain alphanumeric characters and underscores ("_"), and must start with an alphabetic character. Param values can be up to 100 characters long.

So, they have length constraints on both Key and Value.

Key: 40 characters long

Value: 100 characters long

Answer 2

You are logging event with a parameter that exceeds the maximum value limit. There was accompanying FA/Error log message with more details that you probably missed.

Here is the list of the Firebase Analytics error codes:
1 - Invalid Firebase project id.
2 - Event name is invalid (empty, too long, invalid characters).
3 - Event parameter name is invalid (empty, too long, invalid characters).
4 - Event parameter value is too long.
5 - Event has more than 25 parameters.
6 - User property name is invalid (empty, too long, invalid characters).
7 - User property value is too long.
8 - App Instance logs more than 500 unique event types.
9 - App Instance sets more than 25 unique user properties.
10 - App Instance exceeds conversion event limit in a single day.
13 - Event name is reserved.
14 - Event parameter name is reserved.
15 - User property name is reserved.
11, 12, 16 - Internal error.