Microsoft .NET (Octonica)

Use .NET and C# with ClickHouse to query Hydrolix

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

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);
        }
    }
}

Updated about 12 hours ago

What’s Next

SQL Compatibility