Seeding SQLite with Entity Framework - Performance Problems

Question

Introduction

I am trying to seed a SQLite DB with Entity Framework but it's unacceptably slow.

I have an entity MyEntity with 5 columns which has a composite key consists of 3 columns.

Initial approach

dbContext.MyEntity.AddOrUpdate(x => new{x.Key1,  x.Key2, x.Key3}, myEntities.ToArray());

This works incredibly slow. 1138 rows in 40 seconds.

Another Try

Then using this, this and this I came up with this block:

using (var scope = new TransactionScope())
{

    DatabaseContext dbContext;

    using (dbContext = new DatabaseContext())
    {

        dbContext.Database.Connection.Open();

        for (int i = 0; i < myEntities.Count; i++)
        {
            dbContext.MyEntity.AddOrUpdate(
                x => new
                {
                    x.Key1,
                    x.Key2,
                    x.Key3

                },
                myEntities.ElementAt(i));

            if (i % 100 == 0)
            {
                dbContext.SaveChanges();
                dbContext.Dispose();
                dbContext = new DatabaseContext();
                dbContext.Database.Connection.Open();
            }

        }
        dbContext.SaveChanges();
        dbContext.Dispose();
    }
    scope.Complete();
}

Sadly, I get:

Message: Test method threw exception: System.Data.SQLite.SQLiteException: database is locked database is locked

Trying with BulkExtensions library

I also tried BulkExtensions library like this: dbContext.BulkInsertOrUpdate(myEntities)

resulted with following exception:

System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.Data.SQLite.SQLiteException: database schema has changed near "0": syntax error

I believe this happens because I haven't provided the information (there is no way to provide) of the composite key.

The Question

How can I seed a SQLite DB in a reasonable time?