CBO:Need to specifically mention that RBO would be used, in case statistics are missing

Just saw this question raised by our SE:
Brent Janorske  11:08 AM

@here Hi Folks - quick question on the Cost Base Optimizer in 7.0 that's been in Developer Preview prior to 7.0 - since the Update Statistics command is required after index creation, what is the net effect if the customer does not run the Update Statistics command?  Does Couchbase Server default back to the prior Rule Based approach?
 
Kamini Jagtiani  11:09 AM

Yes.Defaults back to Rule Based.
 
Brent Janorske  11:14 AM

Perfect - thanks @Kamini Jagtiani!
 
After I answered I went back and looked at the doc:
https://docs.couchbase.com/server/7.0/n1ql/n1ql-language-reference/cost-based-optimizer.html
We actually don't specifically mention that if we don't have statistics, we default to rule-based
We say:

You can also activate or deactivate the cost-based optimizer using the Query Settings in the Couchbase Web Console.
If the cost-based optimizer is not active, the Query service falls back on the rules-based N1QL optimizer.
 
We should also add:
"In absence of statistics, the Query service falls back on the rules-based N1QL optimizer."