Create Json with a lot of Data and Return with WebApi

Scenario: I have a WebApi that runs a method on my service layer that executes a query either returns 500k result lines, containing 90 columns.

Method that queries and traverses results:

   using (var command = Session.Connection.CreateCommand())
   {
      command.CommandText = dataSource.Query;

      var name = "";

      using (var reader = command.ExecuteReader())
      {
         while (reader.Read())
         {

         }
      }
   }

Today to try to build a JSON I use the JsonTextWriter class:

StringBuilder sb = new StringBuilder(int.MaxValue);
StringWriter sw = new StringWriter(sb);

using (JsonWriter jrWriter = new JsonTextWriter(sw))
{
   using (var command = Session.Connection.CreateCommand())
   {
      command.CommandText = dataSource.Query;

      var name = "";

      using (var reader = command.ExecuteReader())
      {
         while (reader.Read())
         {
            int fields = reader.FieldCount;

            jrWriter.WriteStartObject();

            for (int i = 0; i < fields; i++)
            {
               jrWriter.WritePropertyName(name);

               name = reader.GetName(i);

               if (reader[i] == null)
               {
                  jrWriter.WriteValue("");
               }
               else if (reader[i] is string)
               {
                  jrWriter.WriteValue(reader[i].ToString().Trim());
               }
               else if (reader[i] is bool)
               {
                  var value = (bool)reader[i];

                  if (value)

                     jrWriter.WriteValue("true");

                  else
                  {

                     jrWriter.WriteValue("false");

                  }
                  else if (reader[i] is DateTime)
                  {
                     jrWriter.WriteValue(DateTime.Parse(reader[i].ToString()));
                  }
                  else
                  {
                    jrWriter.WriteValue(reader[i].ToString().Trim().Replace(",", "."));
                  }

                  jrWriter.WriteEndObject();
             }
       }
  }

}

Problem:

After iterating 150k records, SystemOutMemoryException is generated.

I have tried several other solutions to try to send this mass of data to the front, but always crash in the same exception.

I have tried to convert each of my records to an array of bytes and include each record in an Array of byte array, so I even managed to iterate through all records, but at the time of returning to the front, the SystemOutMemoryExeption .

If someone has already had to send a lot of data through the webApi, I'm open to receiving tips to do this better, because I believe the problem is always having to convert everything to string.