MongoDB C# Driver 'Cursor not found' with Linq query

Question

I'm trying to do a select at a Mongo database I'm using this DLL

MongoDB.Bson,MongoDB.Driver,MongoDB.Driver.Linq

My table have more than 55k rows

After some time occurs this error

Cursor Not Found

Here is my code

var client = new MongoClient(connectionString);        
var server = client.GetServer();        
var database = server.GetDatabase("Database");
var collection = database.GetCollection<DesktopSessions>("desktop_sessions");
var query = (from e in collection.AsQueryable<DesktopSessions>()
            where e.created_at > new DateTime(2012, 7, 1)
            select e);
foreach (var item in query)
{
    string id = item._id.ToString();
}

How can I solve this problem?

If you put the new DateTime() into a variable first, then run the query does it work better? — Matt
– Matt, Commented Jan 30, 2014 at 22:17
how much time is some time? you could maybe reach a timeout on the cursor — i3arnon
– i3arnon, Commented Jan 30, 2014 at 22:30
@I3arnon The default timeout for a cursor is 10 minutes. Unless the noTimeout flag is set. — Pete Garafano
– Pete Garafano, Commented Jan 30, 2014 at 22:32
How can I change the timeout? the process takes more than 10 minutes — José Arthur Ortiz Antunes
– José Arthur Ortiz Antunes, Commented Jan 30, 2014 at 22:33
Please note that is 10 minutes of inactivity so if the cursor is iterating it is not timing out. It might help to add more specific information on what is happening in the loop and the actual timings, rows iterated etc. — Neil Lunn
– Neil Lunn, Commented Jan 31, 2014 at 0:17

José Arthur Ortiz Antunes · Accepted Answer · 2014-01-31 12:39:13Z

2

I changed my code to this

 var collection = database.GetCollection<DesktopSessions>("desktop_sessions");
 var queryM = Query.GTE("created_at", new BsonDateTime(new DateTime(2012,7,1)));
 var cursor = collection.Find(queryM);
 cursor.SetFlags(QueryFlags.NoCursorTimeout);

It Works!!

answered Jan 31, 2014 at 12:39

José Arthur Ortiz Antunes

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1 Comment

Pete Garafano Over a year ago

If you fail to exhaust the cursor, the server will never clean it up, and it will be a resource leak, where the resources won't be cleaned up until the mongod process is restarted. It is important to exhaust the cursor or find a way to do it without NoCursorTimeout.

Jiří Herník · Accepted Answer · 2016-10-06 09:25:52Z

0

Other option is to set the timeout for whole database which is what I am doing. You can do it in configuration, command line, mongo shell, or even C#.

see here: https://jira.mongodb.org/browse/SERVER-8188

This is the solution I am using currently in my init class

var db = this.MongoClient.GetDatabase("admin");
var cmd = new BsonDocumentCommand<BsonDocument>(new BsonDocument {
  { "setParameter", 1 },
  { "cursorTimeoutMillis", 3600000 } 
});
db.RunCommand(cmd);

More information could be find here: https://docs.mongodb.com/v3.0/reference/parameters/#param.cursorTimeoutMillis

answered Oct 6, 2016 at 9:25

Jiří Herník

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