Question

I have a complete dictionary of some 236000 words.

I inserted all words from the text file into and SQL server DB and a MongoDb ensuring an index on both DB’s on the the word field.

I loop through all mongo documents inserting each word into a Dictionary in C#
It takes 2.5 seconds. Sometimes slightly less sometimes slightly more.

I loop through all words in a text file inserting them into Dictionary in C#
It takes 0.9 seconds. Sometimes slightly less sometimes slightly more.

I loop through all words in the SQL DB inserting words into a Dictionary in C#
It takes 1.1 seconds. Sometimes slightly less sometimes slightly more.

Should MongoDB be quicker?

MongoDB:

var connectionString = "mongodb://localhost";
            var client = new MongoClient(connectionString);
            var server = client.GetServer();
            var database = server.GetDatabase("test");
            var collection = database.GetCollection<Entity>("entities");

            var cursor = collection.FindAll();

            foreach (Entity book in cursor)
            {
                string name = book.Name;
                string a = Alphabetize(name);
                string value;
                if (dictionary.TryGetValue(a, out value))//http://www.dotnetperls.com/anagram
                {
                    dictionary[a] = value + " " + name;
                }
                else
                {

                    dictionary.Add(a, name);

                }
            }

Ignore the fact the it says “book” and “name” I haven’t changed them yet.

SQL server:

 connection.ConnectionString = ConnectionStrings.connectionString1;
            using (connection)
            using (SqlCommand command = new SqlCommand())
            {
                command.Connection = connection;
                command.CommandText = "SELECT Word FROM Dictionary";
                if (connection.State != ConnectionState.Open) connection.Open();
                using (SqlDataReader sqlReader = command.ExecuteReader())
                {
                    while (sqlReader.Read())
                    {
                        string line = sqlReader.GetString(0);

                        // Alphabetize the line for the key
                        // Then add to the value string
                        string a = Alphabetize(line);
                        string value;
                        if (dictionary.TryGetValue(a, out value))//http://www.dotnetperls.com/anagram
                        {
                            dictionary[a] = value + " " + line;
                        }
                        else
                        {

                            dictionary.Add(a, line);

                        }

                    }

}
}

Each time SQL server performs quicker than MongoDB and the Text file approach performs quicker than both.

I did however notice that insertion for all words was quicker for mongo but that’s not what I’m looking to do.

Is there a quicker way to loop through collections in mongo?

Querying the Text file for a specific word is obviously a lot slower but the performance difference for mongo and SQL weren’t too significant.
0.0450026-ish using mongo. usually quicker
0.0480027-ish using SQl server

Shall I be doing something different with this mongo loop? It’s more than 2 times slower than SQL server…

Answer 1

Both the SQL server and MongoDB need to setup a network connection to your client, execute your query and serialize/unserialize results. This will always be slower than reading from a plain file if you don’t use any indexes or execute more complex queries. Its also a pretty pointless use case for a database. For MongoDB performance is even worse as its a schema less database and it needs to create records in your results dynamically instead of following a fixed table schema.