We tag each query for profiling using _addSpecial and $comment:

db.test.find(

{field:"value"}

)._addSpecial("$comment", "[COMMENT]")

These show up correctly in the logs and db.currentOp() when using collection.find() method.

But any flags added via _addSpecial are not used by the collection's getCount() method. We use the count method to display a query's total count:

db.test.find(

{field:"value"}

).count()
db.test.find(

{field:"value"}

)._addSpecial("$comment", "[COMMENT]").count()

The .count() disregards any special flags, so profiling/tracing/db.currentOp() do not show our unique tag for that query.

Based on the source code, the DBCollection.getCount() method does not accept any special flags parameters, so it looks like a core server issue.

See attached console session, where a .find()._addSpecial shows the $comment via db.currentOp(), but it is not displayed when I issue a .find()._addSpecial().count()