RedisPublishOutstandingPosts.cs

public void PusblishOutstandingPosts(CancellationToken stoppingToken)
{
    const string script = @"if tonumber(redis.call('ZADD', @key1, @timestamp, @value)) == 0 then 
                                return redis.call('GET', @key2) 
                            else 
                                return redis.call('INCR', @key2)
                            end";
    var prepared = LuaScript.Prepare(script);

    var cache = _muxer.GetDatabase();
    for (int i = 0; i < _connectionStrings.Count; i++)
    {
        cache.StringGet("Shard:" + i + ":LastPostId").TryParse(out long lastPostId);
        using var dbContext = new PostServiceContext(_connectionStrings[i]);
        foreach (var post in dbContext.Post.Where(p => p.PostId > (int)lastPostId).OrderBy(p => p.PostId))
        {
            var res = prepared.Evaluate(cache, new { 
                key1 = (RedisKey)"{User:" + post.UserId +"}:PostsByTimestamp",
                key2 = (RedisKey)"{User:" + post.UserId + "}:PostCount",
                timestamp = post.TimeStamp.ToString(),
                value = post.PostId.ToString()});
            cache.Execute("ZADD", new object[] { "UsersByPostCount", "GT", int.Parse(res.ToString()), post.UserId }, CommandFlags.FireAndForget);
            lastPostId = post.PostId;                  
        }
        cache.StringSet("Shard:" + i + ":LastPostId", lastPostId);
    }
}