C# - What are Some High Performance Best Practices/Tips for ADO.NET

.net, ado.net, c#, performance

Solution

One error I see repeated over and over again:

Instantiating and setting up everything (DbConnection, DbCommand, DbParameters) inside a method which is called repeatedly in a tight loop.

Most of the time you can refactor those local variables as class members instantiating them only once and keeping only the updates to DbParameters inside the method.

UPDATED to include sample code asked for in the comments

Disclaimer: This is a quick assembled sample for the sole intent of demonstrating the point about moving repetitive stuff out of the loop. Other better practices aren't necessarily implemented.

        public static void Show() {
            List people = new List();

            //Everything is done inside the loop
            PersonDal personDal = new PersonDal();
            foreach (Person person in people) {
                personDal.Insert(person);
            }

            //Things are setup once outside the loop.
            using (DbConnection connection = SqlClientFactory.Instance.CreateConnection()) {
                // setup the connection
                BetterPersonDal betterPersonDal = new BetterPersonDal(connection);
                connection.Open();
                foreach (Person person in people) {
                    betterPersonDal.Insert(person);
                }
            }
        }
    }

    class Person {
        public int Id { get; set; }
        public string Name { get; set; }
    }

On this first implementation, every thing is set up every time the method is called:

class PersonDal {
    public int Insert(Person person) {
        DbProviderFactory factory = SqlClientFactory.Instance;

        using (DbConnection connection = factory.CreateConnection()) {
            connection.Open();

            connection.ConnectionString = "Whatever";

            using (DbCommand command = connection.CreateCommand()) {
                command.CommandText = "Whatever";
                command.CommandType = CommandType.StoredProcedure;

                DbParameter id = command.CreateParameter();
                id.ParameterName = "@Id";
                id.DbType = DbType.Int32;
                id.Value = person.Id;

                DbParameter name = command.CreateParameter();
                name.ParameterName = "@Name";
                name.DbType = DbType.String;
                name.Size = 50;
                name.Value = person.Name;

                command.Parameters.AddRange(new DbParameter[] { id, name });

                return (int)command.ExecuteScalar();
            }
        }
    }
}

Now we move the setup to the objects construction leaving it out of the loop:

class BetterPersonDal {
    private DbProviderFactory factory;
    private DbConnection connection;
    private DbCommand command;
    private DbParameter id;
    private DbParameter name;

    public BetterPersonDal(DbConnection connection) {
        this.command = connection.CreateCommand();
        this.command.CommandText = "Whatever";
        this.command.CommandType = CommandType.StoredProcedure;

        this.id = command.CreateParameter();
        this.id.ParameterName = "@Id";
        this.id.DbType = DbType.Int32;

        this.name = command.CreateParameter();
        this.name.ParameterName = "@Name";
        this.name.DbType = DbType.String;
        this.name.Size = 50;

        this.command.Parameters.AddRange(new DbParameter[] { id, name });
    }

    public int Insert(Person person) {
        this.id.Value = person.Id;
        this.name.Value = person.Name;

        return (int)command.ExecuteScalar();
    }
}

Problem

Original source