System.Data.SQLite

I noticed this while using SQLite with System.Data.SQLite while writing an application that queried the database very often.

The working memory set for  the application kept growing, so i started .NET Memory Profiler and checked. I noticed that literally ten-thousands of SQLiteCommand objects are noted as undisposed, if i let the application run as much as 5 minutes. And the number increased fast.

I checked the call-stack and all of them were created from either SQLiteCommand.Clone() which is called from System.Data.Entity!System.Data.Common.DbCommandDefinition.CreateCommand() or SQLiteFactory.CreateCommand() which is called from System.Data.Entity!System.Data.EntityClient.EntityCommand.get_CommandTimeout()

Since the two SQLite methods aren't the problem it has to be the EF, so i used the northwind database to perform a quick test.

This:

            while (true)
            {
                using (northwindEFEntities db = new northwindEFEntities())
                {
                    db.Customers.MergeOption = System.Data.Objects.MergeOption.NoTracking;
                    int count = db.Customers
                        .Count()
                    ;
                    count++;
                }
            }

will create a small but steadily growing leak, while this:

            SQLiteConnectionStringBuilder builder = new SQLiteConnectionStringBuilder();
            builder.DataSource = @".\northwindEF.db";
            string sql = @"SELECT count(*) FROM Customers";
            while (true)
            {
                using (SQLiteConnection cnn = new SQLiteConnection(builder.ConnectionString))
                {
                    cnn.Open();
                    using (SQLiteCommand com = new SQLiteCommand(sql, cnn))
                    {
                        int count = Convert.ToInt32(com.ExecuteScalar());
                        count++;
                    }
                }
            }

provides no leak at all.

Seems like the EF doesn't disposes it's commands correctly.

Hi Schuck, I have not tried to run your test yet. But think you are right, it seem there is a memory issue with SQLite.Net EF.

In my Silverlight client/server application, I am using SQLite.net EF in the server side. I found that the memory increases very quickly and it does not decrease as expecting. I always have to reset IIS 2 times/1 day to clear the memory. My application's old version used Access db and I did not see this problem. My other application that only uses SQLite.net without EF also works fine, no memory leak problem.