Enterprise Library Database.ExecuteNonQuery hidden performance issues (Connecting to IBM iSeries)

m_asi = DatabaseFactory.CreateDatabase("ASI-TEST");
using (var cmd = new OleDbCommand())
{
    cmd.CommandType = CommandType.StoredProcedure;
    cmd.CommandText = string.Format("{0}.P_VNDR_INV", m_strASISprocCatalog);
    cmd.Parameters.Add("@RUN_ENV", OleDbType.Char, 1).Value = strEnvironmentCode;
    cmd.Parameters.Add("@SIS_KEY", OleDbType.Char, 36).Value = InvFilter.SISKey;
    cmd.Parameters.Add("@FROM_DTE", OleDbType.Char, 8).Value = InvFilter.CheckDateFrom.ToString("yyyyMMdd");
    cmd.Parameters.Add("@TO_DTE", OleDbType.Char, 8).Value = InvFilter.CheckDateTo.ToString("yyyyMMdd");
    cmd.Parameters.Add("@EXT_Y", OleDbType.Char, 1).Value = (InvFilter.IsExternal ? "Y" : "N");
    cmd.Parameters.Add("@INC_Y", OleDbType.Char, 1).Value = (InvFilter.IncludeASI ? "Y" : "N");
    cmd.Parameters.Add("@VND_ID", OleDbType.Char, 1800).Value = InvFilter.GetVendorQueryString(18, 1800);

    // This call is the bottleneck
    m_asi.ExecuteNonQuery(cmd);
}