When the client starts building LP, it converts double and float values to a string:

                if (value is double || value is float)
                {
                    sb.Append(((IConvertible)value).ToString(CultureInfo.InvariantCulture));
                }

However, CultureInfo.InvariantCulture may not preserve full precision.

Whereas, if that's replaced with "R" the precision will be maintained:

For example

using System;
using System.Globalization;
					
public class Program
{
	public static void Main()
	{
		double a = (double) 459.29587181322927;
		
		string b = a.ToString(CultureInfo.InvariantCulture);
		Console.WriteLine(b);
		
		string c = a.ToString("R");
		Console.WriteLine(c);
		
	}
}

Generates

459.295871813229
459.29587181322927

However, this isn't a full solution, because the use of R may also add unexpected precision. If we redefine a to be 45.29587181323112 in the example above, then we get 45.295871813231123 because of the way that C# handles conversion.

Steps to reproduce:
List the minimal actions needed to reproduce the behavior.

1. Use the client
2. Define a double with >15 significant numbers
3. Write into InfluxDB

Expected behavior:
The full precision should be sent

Actual behavior:
The value will have lost precision

Specifications:

• Client Version:
• InfluxDB Version: 1.x/2.x
• Platform: 4.7.0