Android Firebase Analytics: predefined and custom parameters not working as expected

Question

I have a native Android project that uses Google Analytics for Firebase for its event reporting. I have a couple events that share the same parameters, but some of these count towards the custom parameter limit while others don't. The events I am using are suggested common events and are using mostly suggested parameters with one or two custom parameters. I have a few questions regarding the way events & parameters are showing up on the Firebase console, using the examples below (you can assume the values provided are the correct datatypes).

BEGIN_CHECKOUT

Bundle bundle = new Bundle();
bundle.putString(FirebaseAnalytics.Param.ITEM_ID, itemId);
bundle.putString(FirebaseAnalytics.Param.ORIGIN, itemOrigin);
bundle.putString(FirebaseAnalytics.Param.DESTINATION, itemDestination);
bundle.putString(FirebaseAnalytics.Param.START_DATE, itemStartDate);
bundle.putString(FirebaseAnalytics.Param.END_DATE, itemEndDate);
bundle.putLong(FirebaseAnalytics.Param.NUMBER_OF_PASSENGERS, itemNumberOfPassengers);
bundle.putString(FirebaseAnalytics.Param.TRAVEL_CLASS, itemTravelClass);
bundle.putString(FirebaseAnalytics.Param.CURRENCY, itemCurrency);
bundle.putDouble(FirebaseAnalytics.Param.VALUE, itemValue);
bundle.putString("travel_type", itemTravelType);
mFirebaseAnalytics.logEvent(FirebaseAnalytics.Event.BEGIN_CHECKOUT, bundle);

In Firebase Analytics, on the events tab, this event shows up as follows:

Another example: ECOMMERCE_PURCHASE

Bundle bundle = new Bundle();
bundle.putString(FirebaseAnalytics.Param.ITEM_ID, itemId);
bundle.putString(FirebaseAnalytics.Param.ORIGIN, itemOrigin);
bundle.putString(FirebaseAnalytics.Param.DESTINATION, itemDestination);
bundle.putString(FirebaseAnalytics.Param.START_DATE, itemStartDate);
bundle.putString(FirebaseAnalytics.Param.END_DATE, itemEndDate);
bundle.putLong(FirebaseAnalytics.Param.NUMBER_OF_PASSENGERS, itemNumberOfPassengers);
bundle.putString(FirebaseAnalytics.Param.TRAVEL_CLASS, itemTravelClass);
bundle.putString(FirebaseAnalytics.Param.CURRENCY, itemCurrency);
bundle.putDouble(FirebaseAnalytics.Param.VALUE, itemValue);
bundle.putString("travel_type", itemTravelType);
mFirebaseAnalytics.logEvent(FirebaseAnalytics.Event.ECOMMERCE_PURCHASE, bundle);

Firebase console:

My questions are:

Why are some parameters "auto-added" to parameter reporting of begin_checkout on the Firebase Console, while others aren't? e.g. destination & start_date vs. item_id & currency
Why don't these "auto-added" parameters show up on my dashboard? Only item_id is shown here.
Why isn't a single parameter "auto-added" to the reporting of ecommerce_purchase? The parameters don't even show up on the list on the left, I need to type in the name of the parameters myself
Are custom parameters shared between different events? For example I have the custom parameter "travel_type". To get this parameter to show on both events, I need to add this parameter to both events manually, thus this parameter counts twice towards the global limit of 10 text parameters?
Am I just completely wrong in assuming that using the predefined parameters should not count towards the custom parameter limit? For example, "item_id" is a predefined parameter, yet it does count towards the global quota, is this intended behaviour?

(Might be related, but my ecommerce_purchase event is marked as a conversion event automatically, and I cannot change this, while I have set begin_checkout as a conversion event manually).

For the record, the data of these events & parameters does show up nicely in the Stream -and DebugViews.

Vesper Vesper · Accepted Answer · 2018-04-24T11:21:09

I'll try.

They are not added because the limit for text parameters is already maxed out (10/10).
You probably have to wait 24 hours after selecting the custom parameters before they are reported in dashboard.
You will indeed need to add them manually, and it does count twice.
The predefined events also have predefined parameters as seen here: https://support.google.com/firebase/answer/6317499?hl=en. item_id probably counts for the global quota since it is not part of the predefined events you are using.

ecommerce_purchase is marked as conversion since it is predefined as a conversion event.

Android Firebase Analytics: predefined and custom parameters not working as expected

1 Answers