I can not find similar mysql syntax "INSERT ... SELECT ..." in mongo for sharded collection.

db.eval() - does not work on sharded collection
MapReduce - too expensive and slow operation

Use case:
Need select documents from one sharded collection, make rearrangement of fields and upsert it to another sharded collection.
Source collection format:
{
"_id": ObjectId("4fcf7349d144ad591c016534"),
"sid": 111,
"uh": "www.site.kz",
"cid": "4facd5427701a",
"ses": "4fcf7278f1f19",
"ip": NumberInt(1597732605),
"t": ISODate("2012-06-06T15: 08: 40.0Z"),
...
}
Destination collection format:
{
"_id":

,
"t": ISODate("2012-06-06T15: 08: 40.0Z"),
}