Apache Ignite.NET SQL indexes: compound, individual, parts of key and value

Program.cs

using Apache.Ignite.Core;
using Apache.Ignite.Core.Cache.Configuration;
using Apache.Ignite.Core.Cache.Query;

using var ignite = Ignition.Start();

var cacheCfg = new CacheConfiguration("people")
{
    QueryEntities = new[]
    {
        new QueryEntity(keyType: typeof(PersonKey), valueType: typeof(Person))
    }
};

var cache = ignite.GetOrCreateCache<PersonKey, Person>(cacheCfg);

var key = new PersonKey
{
    Id = 1,
    Company = "Acme"
};

var person = new Person
{
    Name = "John",
    Country = "Brazil",
    Department = "Sales"
};

cache[key] = person;

// Uses individual index: "people".PERSON_COUNTRY_ASC_IDX
PrintResults(cache.Query(new SqlFieldsQuery("explain select name from person where country = ?", "Brazil")));

// Uses compound index: "people".PERSON_COMPANY_ASC_DEPARTMENT_ASC_IDX
PrintResults(cache.Query(new SqlFieldsQuery("explain select name from person where company = ?1 and department = ?2", "Acme", "Sales")));

void PrintResults(IFieldsQueryCursor cursor) =>
    Console.WriteLine("\n>>> " + string.Join(Environment.NewLine, cursor.Select(row => string.Join(", ", row))));

public class PersonKey
{
    public long Id { get; set; } // Not visible in SQL

    [QuerySqlField(IsIndexed = true, IndexGroups = new[] { "IndexGroup1" })] // Visible in SQL, group index 1
    public string? Company { get; set; }
}

public class Person
{
    [QuerySqlField] // Visible in SQL, no index.
    public string? Name { get; set; }

    [QuerySqlField(IsIndexed = true, IndexGroups = new[] { "IndexGroup1" })] // Visible in SQL, group index 1
    public string? Department { get; set; }

    [QuerySqlField(IsIndexed = true)] // Visible in SQL, individual index.
    public string? Country { get; set; }
}