I did a query that generated no shards
s.adminCommand( { shardcollection: '' + c, key:
{ a:1,b:1 } } );
printjson( c.find({a:1,b:{$gt:4,$lt:2}}).explain() );
{
"clusteredType" : "ParallelSort",
"shards" : {
},
"millisTotal" : 0,
"millisAvg" : -2147483648,
"numQueries" : 0,
"numShards" : 0
}
The millisAvg value seems strange - just a guess, perhaps a variable is left uninitialized to avoid a divide by zero error?