JonCole

Some of the Redis best practices content has moved

This content from this markdown file has moved a new, happier home where it can serve more people. Please check it out : https://docs.microsoft.com/azure/azure-cache-for-redis/cache-best-practices.

NOTE: Client specific guidance listed below is still valid and should still be considered. I will update this document once all content has been moved.

JonCole

ThreadPool Growth: Some Important Details

The CLR ThreadPool has two types of threads - "Worker" and "I/O Completion Port" (aka IOCP) threads.

• Worker threads are used when for things like processing Task.Run(…) or ThreadPool.QueueUserWorkItem(…) methods. These threads are also used by various components in the CLR when work needs to happen on a background thread.
• IOCP threads are used when asynchronous IO happens (e.g. reading from the network).

The thread pool provides new worker threads or I/O completion threads on demand (without any throttling) until it reaches the "Minimum" setting for each type of thread. By default, the minimum number of threads is set to the number of processors on a system.

Once the number of existing (busy) threads hits the "minimum" number of threads, the ThreadPool will throttle the rate at which is injects new threads to one thread per 500 milliseconds. This means that if your system gets a burst of work needing an IOCP thread, it will proces

JonCole

Debugging Redis Keyspace Misses

Simply put, a keyspace "MISS" means some piece of data you tried to retrieve from Redis was not there. This usually means that one of the following things happened:

1. The key expired
2. They key was renamed
3. The key was deleted
4. The key was evicted due to memory pressure
5. The entire database was flushed
6. The key was never actually inserted

JonCole

using System;

namespace StackExchange.Redis
{
    static class RedisKeyspaceNotifications
    {
        /// <summary>
        /// NOTE: For this sample to work, you need to go to the Azure Portal and configure keyspace notifications with "Kxge$" to
        ///       1) turn on expiration notifications (x), 
        ///       2) general command notices (g) and 

JonCole

Diagnosing Redis errors on the server side

The content from this GIST has been moved to official Azure Cache for Redis Documentation. The new location is https://docs.microsoft.com/azure/azure-cache-for-redis/cache-how-to-troubleshoot#server-side-troubleshooting

Please update your bookmarks.

JonCole

The Symptom

An application is using StackExchange.Redis to connect to their Redis instance and everything is working fine until suddenly exceptions like this start happening.

It was not possible to connect to the redis server(s); to create a disconnected multiplexer, disable AbortOnConnectFail.
at StackExchange.Redis.ConnectionMultiplexer.ConnectImpl(Func`1 multiplexerFactory, TextWriter log)
at MyApp.Web.Redis.StackExchangeClientConnection..ctor(ProviderConfiguration configuration)
at MyApp.Web.Data.GetInventoryData()

The Cause

JonCole

Summary

Unless otherwise noted, all source code under https://gist.github.com/joncole is licensed using a slightly modified MIT License. Key difference is that you don't have to copy this license with the source code/samples given here.

Modified MIT License

Copyright 2018 Jon Cole

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AU

JonCole

Diagnosing Redis errors on the client side

Content moved

The content from this GIST has been moved to official Azure Cache for Redis Documentation. The new location is https://docs.microsoft.com/azure/azure-cache-for-redis/cache-troubleshoot-client

Please update your bookmarks.

JonCole

Contents Moved

The contents of this article have moved to a new, happier home https://aka.ms/Redis/DataLoss

JonCole

Content Moved

The content from this article has been moved to a happier home on our official documentation site - please update your bookmarks.