efcore.pg: "A command is already in progress" - connection pooling default configuration failing

Hi,

When using default pooling configuration on localhost DB, I have plenty of “a command is already in progress”, and sometimes, “connection already open” issues. I use traditional connection procedure services.AddEntityFrameworkNpgsql().AddDbContextPool<DBApiContext>(opt => opt.UseNpgsql(configuration.GetConnectionString("DBConnection"))); Connection String only activates Pooling=true. "DBConnection": "User ID=****;Password=****;Server=localhost;Port=5432;Database=*****;Pooling=true;", I used postgresql v9.5 and v10. .NETCore and PostgreSQL are hosted on the same machine. It sounds like the Pooling has not started ?

By the way, the connection to the DB is very easy:

var userQuery = this._db.PlaPlayer.Where(p => p.Nickname==credent.username);
if( userQuery.Count() != 1 ) 

Is there any way to track the Pooling activity? Or to enable it ? The model is easy too:

	public partial class DBApiContext : DbContext
	{
		public virtual DbSet<PlaPlayer> PlaPlayer { get; set; }

		public DBApiContext(DbContextOptions<DBApiContext> options)
			: base(options)
		{ }

		protected override void OnModelCreating(ModelBuilder modelBuilder)
		{
			modelBuilder.Entity<PlaPlayer>(entity =>
			{
				entity.ToTable("pla_player");

				entity.Property(e => e.Id)
					.HasColumnName("id");

				entity.HasIndex(e => e.Nickname)
					.HasName("nickname_unique")
					.IsUnique();

				entity.Property(e => e.Nickname)
					.IsRequired()
					.HasColumnName("nickname");
			});
		}
	}