mongodb unwind aggregate result? - mongodb

Question

So I'm trying to produce some statistics in my database using aggregation
My current script looks like this:
db.posts.aggregate( [
{ $group: {_id : "$domain", "counter" : {$sum : 1}}},
{ $sort : { counter : -1}},
{ $match : { counter : {$gt : 10} } }
])
and produces result like this:
{
"result" : [
{
"_id" : "i.imgur.com",
"counter" : 1220
},
{
"_id" : "imgur.com",
"counter" : 459
}
],
"ok" : 1
}
Quite satisfactory, but I want to move further. I'm using robomongo (more comfortable to me) and this appears like single document to me:
I want to have each result to be a separate document like this:
| _id | counter
---+-------------+--------
1 | i.imgur.com | 1220
---+-------------+--------
2 | imgur.com | 459
I assumed I needed to use $unwind, but failed miserably: adding { $unwind : "$result"} to aggregate chain produces this output:
/* 0 */
{
"result" : [],
"ok" : 1
}
What have I done wrong and how to do it right?

Answer 1

I don't use robomongo, but it seems like you could tack on .result to your script to get the results output you want.
db.posts.aggregate( [
{ $group: {_id : "$domain", "counter" : {$sum : 1}}},
{ $sort : { counter : -1}},
{ $match : { counter : {$gt : 10} } }
]).result
I've done some looking into this and it appears that the return output you are getting is a consequence of robomongo using db.posts.runCommand("aggregate", {pipeline: [<array of pipeline operators>]}) and then not "instantiating a cursor" rather than the aggregate() helper which creates a cursor.
I don't think there's much you can do on this outside of filing a ticket.