Azure redis cache SetString multiplexer error

Question

I'm attempting to use Azure redis cache to reduce hits to my database, but I'm stuck on something very weird. My WebMethod looks as such.

[WebMethod]
public static string HistoricalData(string searchterm, string topicId)
    {
        string constr = ConfigurationManager.ConnectionStrings["Azure"].ConnectionString;
        var lazyConnection = new Lazy<ConnectionMultiplexer>(() => {
            string cacheConnection = ConfigurationManager.ConnectionStrings["CacheConnection"].ToString();
            return ConnectionMultiplexer.Connect(cacheConnection);
        });

        JavaScriptSerializer json = new JavaScriptSerializer();
        List<HistoricalGraph> hg = new List<HistoricalGraph>();

        json.MaxJsonLength = Int32.MaxValue;

        IDatabase cache = lazyConnection.Value.GetDatabase();
        var cachedCategory = cache.StringGet(topicId).ToString();

        if (cachedCategory == null){
            using (SqlConnection conn = new SqlConnection(constr))
            {
                conn.Open();
                using (SqlCommand cmd = new SqlCommand("my_sp", conn))
                {
                    cmd.CommandType = CommandType.StoredProcedure;
                    cmd.Parameters.AddWithValue("@Type", "GetData");
                    cmd.Parameters.AddWithValue("@Topic", searchterm);

                    using (SqlDataReader r = cmd.ExecuteReader())
                    {
                        if (r.HasRows)
                        {
                            while (r.Read())
                            {
                                hg.Add(new HistoricalGraph
                                {
                                    asin = r.GetValue(0).ToString() ?? "",
                                    title = r.GetValue(1).ToString() ?? "",
                                    tagBrand = r.GetValue(2).ToString() ?? "",
                                    TagFieldValue1 = r.GetValue(3).ToString() ?? "",
                                    TagFieldValue2 = r.GetValue(4).ToString() ?? "",
                                    TagFieldValue3 = r.GetValue(5).ToString() ?? "",
                                    TagFieldValue4 = r.GetValue(6).ToString() ?? "",
                                    TagFieldValue5 = r.GetValue(7).ToString() ?? "",
                                    pack = r.GetValue(8).ToString() ?? "",
                                    date = r.GetValue(9).ToString() ?? "",
                                    avgPrice = r.GetValue(10).ToString() ?? "",
                                    units = r.GetValue(11).ToString() ?? "",
                                    revenue = r.GetValue(12).ToString() ?? "",
                                    image = r.GetValue(13).ToString() ?? ""
                                });
                            }

                        }
                    }
                }
            }
            System.Diagnostics.Debug.WriteLine("From SQL");

            var serializedData = json.Serialize(hg);
            cache.StringSet(topicId, serializedData).ToString(); //Errors here

            return serializedData;
        }
        else
        {
            System.Diagnostics.Debug.WriteLine("From Redis Cache");

            return cachedCategory.ToString();
        }
    }

StackExchange redis throws a multiplexer error that isn't very descriptive, but the kicker is if i reload the page it successfully pulls the json data from my redis cache. The json string is on average about 8MB. Any thoughts or suggestions on this issue would be greatly appreciated.

What is the error, and is there an exception associated with it? If so, what are its details? — Frank Alvaro, Apr 26 '20 at 13:14

score 0 · Answer 1 · answered Apr 27 '20 at 20:20

The error thrown looked something like this:

System.TimeoutException: Timeout performing MGET 2728cc84-58ae-406b-8ec8-3f962419f641, inst: 1,mgr: Inactive, queue: 73, qu=6, qs=67, qc=0, wr=1/1, in=0/0
IOCP: (Busy=6, Free=999, Min=2,Max=1000), WORKER (Busy=7,Free=8184,Min=2,Max=8191)

I changed a few things to get it working.

First I deleted and recreated the cache, leaving TLS at its default value. Then to reduce the size of the response, I compress and decompress the string. Bringing the size down to a more manageable 1MB. Fingers crossed, but I haven't received the multiplexer error since.

score 0 · Answer 2 · answered Feb 08 '22 at 18:06

0

Check if you are storing data in JSON format or not. Next, you need to Deserialize the json data under topicId value

answered Feb 08 '22 at 18:06

Sanju Kushwaha

61
4

Azure redis cache SetString multiplexer error

2 Answers2