The issue that your having is due to the way Entity Framework does its internal cache.
In order to increase performance, Entity Framework will cache entities to avoid doing a database hit.
Entity Framework will update its cache when you are doing certain operations on DbSet.
Entity Framework does not understand that your "DELETE FROM ... WHERE ..."
statement should invalidate the cache because EF is not an SQL engine (and does not know the meaning of the statement you wrote). Thus, to allow EF to do its job, you should use the DbSet methods that EF understands.
for (var email in db.v2EmailQueues.OrderBy(c => c.ID).Take(Settings.EMAILS_PER_BATCH))
{
// whatever your amazon code was...
if (sent)
{
db.v2EmailQueues.Remove(email);
}
else
{
email.FailCount++;
}
}
// this will update the database, and its internal cache.
db.SaveChanges();
On a side note, you should leverage the ORM as much as possible, not only will it save time debugging, it makes your code easier to understand.