MongoDB C# low performance issue - performance

Question

I'm testing MongoDB 1.6.5 speed and C# in win64 machine. I use Yahoo.geoplanet as source to load states, county, towns but i'm not very performant. I have currently more 5 sec to load the US states from these source passing a List to a web page in localhost.
Use only id as index. Can someone suggest way to perform. Thanks
class BsonPlaces
{
[BsonId]
public String Id { get; set; }
public String Iso { get; set; }
public String Name { get; set; }
public String Language { get; set; }
public String Place_Type { get; set; }
public String Parent_Id { get; set; }
}
public List<BsonPlaces> Get_States(string UseCountry)
{
using (var helper = BsonHelper.Create())
{
var query = Query.EQ("Place_Type", "State");
if (!String.IsNullOrEmpty(UseCountry))
query = Query.And(query, Query.EQ("Iso", UseCountry));
var cursor = helper.GeoPlanet.PlacesRepository.Db.Places
.FindAs<BsonPlaces>(query);
if (!String.IsNullOrEmpty(UseCountry))
cursor.SetSortOrder(SortBy.Ascending("Name"));
return cursor.ToList();
}
}

Answer 1

I suppose problem not in mongodb, loading can be slow for two reasons:
You trying to load big count of 'BsonPlaces'(20000 for example or even more).
Some another code on page take much time.
For speed improvements you can:
1.Set limit to items that will be returned by query:
cursor.SetLimit(100);
2.Create indexes for 'Name', 'Iso', 'Place_Type':
helper.GeoPlanet.PlacesRepository.Db.Places.EnsureIndex("Name");

Answer 2

c# driver probably have big performance problem. A simple query for 100k times on shell takes 3 seconds, same query (written in c# linq of official c# driver 1.5) takes 30 seconds. Profiler tells each query from c# client takes less than 1 ms. So I assume c# driver is doing a lot of unnecessary stuffs that makes the query so slow.
Under mongodb 2.0.7, OS: windows 7, Ram: 16G.

Answer 3

I downloaded the GeoPlanet Data from Yahoo and found that the geoplanet_places_7.6.0.tsv file has 5,653,969 lines of data.
That means that in the absence of an index you are doing a "full table scan" of over 5 million entries to retrieve the 50 US states.
When querying for states within a country, the following index would probably be the most helpful:
...EnsureIndex("Iso", "Place_Type");
Not sure why you would want to search for all "States" without specifying a country, but you would need another index for that.
Sometimes when a sort is involved it can be advantageous for the index to match the sort order. For example, since you are sorting on "Name" the index could be:
...EnsureIndex("Iso", "Place_Type", "Name");
However, with only 50 states the sort will probably be very fast anyway.
I doubt any of your slow performance is attributable to the C# driver, but if after adding the indexes you still have performance problems let us know.