- 
    Type:Improvement 
- 
    Resolution: Won't Do
- 
    Priority:Major - P3 
- 
    None
- 
    Affects Version/s: None
- 
    Component/s: Index Maintenance
- 
        Storage Execution
- 
        (copied to CRM)
- 
        None
- 
        None
- 
        None
- 
        None
- 
        None
- 
        None
- 
        None
We should consider reporting a warning if an index build on a non-empty collection does not encounter any documents containing the key(s) specified. This can happen, for example, if there is a typo in the command. Such a warning could help mitigate performance issues and reduce the time and resources required to investigate and correct.
> db.bar.findOne()
{
	"_id" : ObjectId("596e1e46970f5ca6dfaaf7d7"),
	"address" : "123 Main Street"
}
>
>//It would be nice if the output of the following command indicated that the misspelled "adress" field was not found while building the index
>
> db.bar.createIndex({adress:1})
{
	"createdCollectionAutomatically" : false,
	"numIndexesBefore" : 1,
	"numIndexesAfter" : 2,
	"ok" : 1
}
> 
> db.bar.find({"address" : "123 Main Street"}).explain()
{
	"queryPlanner" : {
		"plannerVersion" : 1,
		"namespace" : "foo.bar",
		"indexFilterSet" : false,
		"parsedQuery" : {
			"address" : {
				"$eq" : "123 Main Street"
			}
		},
		"winningPlan" : {
			"stage" : "COLLSCAN",
			"filter" : {
				"address" : {
					"$eq" : "123 Main Street"
				}
			},
			"direction" : "forward"
		},
		"rejectedPlans" : [ ]
	},
}