// Make sure the database can be sharded.
sh.enableSharding(dbname);

// Shard the collection on the { _id : 1 } key.
sh.shardCollection(fullName, {"_id" : 1 }, true)

// Also consider sharding on the index { _id : "hashed" }.
// That will work well for all YCSB operations except a scan
// and you can then skip the rest of this script since you can
// ask MongoDB to create and balance the empty collection with a
// command like:
//   sh.shardCollection(fullName,
//                      { "_id" : "hashed" },
//                      false,
//                      { numInitialChunks : shardDocs.length * 10 });

// Figure out the names of the shards.
var shards=[];
for ( var shardDocIndex in shardDocs ) {
  var shardDoc = shardDocs[shardDocIndex];
  if( shardDoc.draining ) {
    print("Not including the draining shard " + shardDoc._id + ".\n");
  } else {
    shards.push(shardDoc._id);
  }
}

print("Splitting " + fullName + " across shards:\n");
for ( var index in shards ) {
  print("  " + shards[index] + "\n");
}

// Split the collection and move chunks around.
var shardIndex = 0;
for ( var i in digits ) {
  for ( var j in digits ) {
    var splitLocation = prefix + digits[i] + digits[j];
    var destination = shards[ shardIndex % shards.length ];
    shardIndex += 1;

    print("Splitting at " + splitLocation + "...");
    sh.splitAt( fullName, { "_id" : splitLocation } );
    print(" moving to " + destination + "...");
    sh.moveChunk( fullName, { "_id" : splitLocation }, destination );
    print(" done.");
  }
}

// Start the balancer again.
sh.startBalancer();