Microsoft .NET (Octonica)

Overview

Query your Hydrolix cluster with .NET and the Octonica ClickHouse client.

Prerequisites

Before you begin, be sure to have the following:

• The .NET SDK installed, version 6.0 or higher
• The Octonica ClickHouse client added to the project
• A working Hydrolix cluster
• The host address, port, and database name
• A valid username and password for authentication
• A local environment that allows outbound connections to the ClickHouse native interface port; default is 9440 with TLS

Query with .NET example

This example sets TLSMode=Require to enforce a secure connection. It connects with a Hydrolix cluster, runs a query, and outputs the results.

Replace the following fields with your cluster information:

• Host
• Database
• User

• Password

  C# Example Code

  using System;
  using System.Threading.Tasks;
  using Octonica.ClickHouseClient;
  using Octonica.ClickHouseClient.Exceptions;
  
  internal static class Program
  {
      public static async Task Main()
      {
          var connStr =
              "Host=<your-cluster-host>;" +
              "Port=9440;" +
              "TLSMode=Require;" +
              "Database=<your-database>;" +
              "User=<your-user>;" +
              "Password=<your-password>;";
  
          try
          {
              await using var conn = new ClickHouseConnection(connStr);
              await conn.OpenAsync();
  
              // Optional: Set logging level to reduce noise
              await using (var s = conn.CreateCommand("SET send_logs_level='fatal'"))
                  await s.ExecuteNonQueryAsync();
  
              const string sql = @"
  SELECT toStartOfHour(timestamp), count()
  FROM   logs
  WHERE  timestamp >= now() - INTERVAL 1 DAY
  GROUP  BY 1
  ORDER  BY 1 DESC";
  
              await using var cmd = conn.CreateCommand(sql);
              await using var r = await cmd.ExecuteReaderAsync();
  
              while (await r.ReadAsync())
              {
                  for (int i = 0; i < r.FieldCount; i++)
                  {
                      Console.Write(i == 0 ? r.GetValue(i) : $"\t{r.GetValue(i)}");
                  }
                  Console.WriteLine();
              }
          }
          catch (ClickHouseException db)
          {
              Console.Error.WriteLine($"Hydrolix/ClickHouse: {db.Message}");
          }
          catch (Exception ex)
          {
              Console.Error.WriteLine(ex);
          }
      }
  }