Why error No connection is available to service this operation: SETEX while writing to Redis Cache in C# console application and how to solve it

Question

I am trying to write records from a dictionary with around 5000 records to a Redis cache. But sometimes I get the below exception, I have no clue why I am getting this error, I have checked on the internet but could not find any solution or root cause of this issue.

using (ConnectionMultiplexer redis = ConnectionMultiplexer.Connect(_configuration.GetConnectionString("redis_server")))
            {
                IDatabase db = redis.GetDatabase();


                foreach (KeyValuePair<string, string> keyValuePair in _dictAllData)
                {
                    db.StringSet(keyValuePair.Key, keyValuePair.Value, TimeSpan.FromMinutes(30));
                }

        }

Exception

No connection is available to service this operation: SETEX 747712; IOCP: (Busy=0,Free=1000,Min=4,Max=1000), WORKER: (Busy=0,Free=32767,Min=4,Max=32767), Local-CPU: n/a

Edit:

StackExchange.Redis version: 2.0.601

Answer 1

Seems like you are running out of connections in the pool (client-side). Besides, performance-wise, one set at a time is bad in this case.

You should be using batching or pipelining. See Pipelining vs Batching in Stackexchange.Redis . It has code examples.

And since it seems you don't care about the response, consider flags: CommandFlags.FireAndForget . See Pipelines and Multiplexers .