When xreadgroup block reads data after a redistimeout, the first message cannot be consumed

[punisher1]

• windows10
• redis 5.0.10
• dotnet any version
• StackExchange.Redis 2.6.111

using StackExchange.Redis;
using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;

class Program
{

    static void Main()
    {

        var config = ConfigurationOptions.Parse("127.0.0.1:6379");
        config.CommandMap = CommandMap.Create(new HashSet<string> { "SUBSCRIBE" }, false);
        var redisRead = ConnectionMultiplexer.Connect(config);
        var redisReadDb = redisRead.GetDatabase(1);

        try
        {
            redisReadDb.StreamCreateConsumerGroup("test", "default", StreamPosition.NewMessages, true);
        }
        catch { }


        var redisWrite = ConnectionMultiplexer.Connect(config);
        var redisWriteDb = redisWrite.GetDatabase(1);

        var writeTask = Task.Run(async () =>
        {
            while (true)
            {
                var id = await redisWriteDb.StreamAddAsync("test", "time", DateTime.Now.ToString());
                var id2 = await redisWriteDb.StreamAddAsync("test", "time", DateTime.Now.ToString());

                Console.WriteLine($"{DateTime.Now:O} write message:{id},{id2}");
                Thread.Sleep(10000);
            }
        });

        var readTask = Task.Run(async () =>
        {
            var arguments = new List<object>
                {
                    "GROUP",
                    "default",
                    $"dotnet",
                    "COUNT",
                    10,
                    "BLOCK",
                    "0",
                    "STREAMS",
                    "test",
                    ">"
                };

            while (true)
            {
                try
                {
                    Console.WriteLine($"{DateTime.Now:O} redis xreadgroup block read ...");

                    var result = await redisReadDb.ExecuteAsync("xreadgroup", arguments).ConfigureAwait(false);
                    if (result.IsNull)
                    {
                        Console.WriteLine($"{DateTime.Now:O} redis xreadgroup isnull");
                    }
                    else
                    {
                        foreach (RedisResult[] subresults in (RedisResult[])result)
                        {
                            var streamName = (RedisValue)subresults[0];

                            foreach (RedisResult[] messages in (RedisResult[])subresults[1])
                            {
                                var id = (RedisValue)messages[0];
                                Console.WriteLine($"{DateTime.Now:O} read message:{id}");
                                await redisReadDb.StreamAcknowledgeAsync("test", "default", id);
                            }
                        }
                    }
                }
                catch (RedisTimeoutException)
                {
                    Console.WriteLine($"{DateTime.Now:O} redis timeout ...");
                }
            }
        });


        Console.ReadLine();
    }
}

2023-05-31T14:25:27.4733370+08:00 redis xreadgroup block read ... 2023-05-31T14:25:27.4976884+08:00 read message:1685514327495-0 2023-05-31T14:25:27.4994336+08:00 write message:1685514327495-0,1685514327498-0 2023-05-31T14:25:27.5082905+08:00 redis xreadgroup block read ... 2023-05-31T14:25:27.5101550+08:00 read message:1685514327498-0 2023-05-31T14:25:27.5107652+08:00 redis xreadgroup block read ... 2023-05-31T14:25:33.4848775+08:00 redis timeout ... 2023-05-31T14:25:33.4851831+08:00 redis xreadgroup block read ... 2023-05-31T14:25:37.5174767+08:00 write message:1685514337514-0,1685514337515-0 2023-05-31T14:25:37.5175269+08:00 read message:1685514337515-0 2023-05-31T14:25:37.5189520+08:00 redis xreadgroup block read ... 2023-05-31T14:25:43.4835083+08:00 redis timeout ... 2023-05-31T14:25:43.4837146+08:00 redis xreadgroup block read ... 2023-05-31T14:25:47.5262835+08:00 write message:1685514347525-0,1685514347526-0 2023-05-31T14:25:47.5262841+08:00 read message:1685514347526-0 2023-05-31T14:25:47.5276668+08:00 redis xreadgroup block read ... 2023-05-31T14:25:53.4743876+08:00 redis timeout ... 2023-05-31T14:25:53.4745574+08:00 redis xreadgroup block read ... 2023-05-31T14:25:57.5292349+08:00 write message:1685514357528-0,1685514357529-0 2023-05-31T14:25:57.5292381+08:00 read message:1685514357529-0 2023-05-31T14:25:57.5314306+08:00 redis xreadgroup block read ...

[haoma2514]

This may be because the "xreadgroup" command has been executed on the server before receiving the "timeout" result? It should never time out when reading is blocked.

[haoma2514]

Maybe you can refer to it https://github.com/StackExchange/StackExchange.Redis/issues/2135