DEV Community: Husni Adil Makmur

Cache-Aside Pattern

Husni Adil Makmur — Sat, 12 Dec 2020 07:29:45 +0000

Introduction

When you develop an app that uses database as storage, i.e. MySQL, you probably need to use a cache layer to help your application serve data more quickly, especially for serving data that's not changed too often. Whether you stored it in application memory or external cache server, i.e. Redis. This is called cache-aside pattern.

When your app receives a request, it'll try to find the data in the cache layer first.

If the data is in the cache (cache hit), it uses that data instead of requesting to database.
If the data is not in the cache (cache miss), it will get the data from database.
Write the copy of data that's obtained from the database into cache layer.

Cached data lifetime

When you're using this strategy, you need to define the lifetime of cached data by defining TTL (Time to live). You need to set the TTL value correctly for getting the most of caching benefit. If you set the period too short, your app may hit your database too often and this could increase latency. In the other hand, when you set the period too long, your app may be in the inconsistent state since it serves stale data. There's no one correct setting for all cases, so you need to find a correct setting that suits your use case.

Time to live (TTL) or hop limit is a mechanism which limits the lifespan or lifetime of data in a computer or network. TTL may be implemented as a counter or timestamp attached to or embedded in the data. Once the prescribed event count or timespan has elapsed, data is discarded or revalidated. In computer networking, TTL prevents a data packet from circulating indefinitely. In computing applications, TTL is commonly used to improve the performance and manage the caching of data.

View on Wikipedia>

Data eviction policies

In some cases, you may be considering and using the data eviction policy in case the cache storage is full. This is very useful when you need to store many objects in the cache on a limited amount of cache storage/memory. There are many policies out there, for example FIFO, LIFO, LRU, ARC, etc. You may choose one that suits for your needs.

In computing, cache replacement policies are optimizing instructions or algorithms which a computer program or hardware-maintained structure can utilize to manage a cache of information. Caching improves performance by keeping recent or often-used data items in memory locations which are faster, or computationally cheaper to access, than normal memory stores. When the cache is full, the algorithm must choose which items to discard to make room for new data.

View on Wikipedia>

If you choose to use Redis, you might want to read the Redis Data Eviction Policies as well.

Another additional mechanism you might need to implement is to manually evict corresponding cached data when there's a write in the database for a particular data.

In-memory cache vs external cache

Choosing caching strategy is always depending on the use case. Both strategies (in-memory cache or external cache) have their own strength.

Using In-memory cache

Pros

Cheap, no need to spawn cache server instance.

Cons

Different cache state when your application has two or more instances, since every instance will have their own managed cache data.

Using external cache

Pros

Shared state, means consistent cached data accross multiple app instances.
Your app doesn't need additional memory to hold all cached data.

Cons

Might be expensive. You have to spend more bucks for having external layers, i.e. Redis servers/clusters.
Additional effort if you manage the servers yourselves.
Network latency.

When to use

There is no silver bullet on solving app performance problem. This is being one of many patterns you can use. All is depending on the use case. You might consider this pattern when:

Your database doesn't have built-in cache layer
Your existing cache layer doesn't have a built-in read-through or write-through operation to the database

But then again, you need to look up on your use case.

Caching static data

If your app only depends on static data, it may not be suitable for using cache-aside pattern. Instead, you may consider:

Loading the data on app startup if possible.
Setting the cached data to never expire.

Cache-aside pattern in Go

Let's go with some coding in Go to demonstrate this pattern.

Since this is a simulation, We're not actually using a real MySQL or Redis instances. Instead, we'll have some simulation. And by the way, this is a very simple example that demonstrate how cache-aside pattern works.

First of all, we need to have an interface that you're gonna use it for simulating a repository that we can implement it later as a MySQL and Redis repositories.

type Repository interface {
  DoAnExpensiveQuery(id string) (*string, error)
}

We have one method here. Both MySQL and Redis implementation should implements this method.

Now we're gonna create the MySQL repository that's responsible for handling communication with MySQL.

package repository

import (
  "errors"
  "fmt"
  "sync"
  "time"
)

type MySQLRepository struct {
  mysqldb sync.Map
}

func NewMySQLRepository() Repository {
  return &MySQLRepository{
    mysqldb: sync.Map{},
  }
}

// demonstrate an expensivev query or frequently accessed query
func (m *MySQLRepository) DoAnExpensiveQuery(id string) (*string, error) {
  if rawData, ok := m.mysqldb.Load(id); ok {
    data := rawData.(string)
    return &data, nil
  }
  return nil, errors.New("record not found")
}

So here we're using sync.Map package to simulate the mysql client. Instead of reading from and writing to real database, we're actually reading from and writing to the Map.

And now, the Redis part.

package repository

import (
  "fmt"
  "time"

  "github.com/bluele/gcache"
)

type RedisRepository struct {
  redis gcache.Cache
  mysql Repository
  ttl   time.Duration
}

func NewRedisRepository(ttl time.Duration, mysql Repository) Repository {
  return &RedisRepository{
    redis: gcache.New(100).LRU().Build(),
    mysql: mysql,
    ttl:   ttl,
  }
}

func (r *RedisRepository) DoAnExpensiveQuery(id string) (*string, error) {
  rawData, err := r.redis.Get(id)
  if err == nil && rawData != nil {
    // if the data is in redis, return it
    fmt.Printf("Cache hit for id: %s\n", id)
    data := rawData.(string)
    return &data, nil
  }

  if err != nil {
    // in case of error, do not return
    // have a try reading from database
    fmt.Printf("Cache miss for id: %s\n", id)
  }

  // if the data is not in the cache yet,
  // get it from database
  result, err := r.mysql.DoAnExpensiveQuery(id)
  if err != nil {
    return nil, err
  }
  // and eventually store the value to cache
  go func(result string) {
    r.redis.SetWithExpire(id, result, r.ttl)
  }(*result)

  return result, nil
}

This part is more complex than the MySQL. The Redis repository depends on MySQL repository as the source of truth.

So basically this adheres to our previous diagram. Let me paste it here so you don't need to scroll up.

When your app receives a request, it'll try to find the data in the cache layer first.

If the data is in the cache (cache hit), it uses that data instead of requesting to database.
If the data is not in the cache (cache miss), it will get the data from database.
Write the copy of data that's obtained from the database into cache layer.

And then we'll have a main function to call them. Notice that we're using decorator pattern to achieve this.

package main

import (
  "fmt"
  "time"

  "github.com/husniadil/cache-aside-pattern/repository"
)

func main() {
  ttl := time.Second * 3

  repo := repository.NewMySQLRepository()
  repo = repository.NewRedisRepository(ttl, repo)

  id := "2c1b7cd2-0420-4b73-a3f9-734504842fb9"

  var names []string
  for i := 0; i < 5; i++ {
    name, err := repo.DoAnExpensiveQuery(id)
    if err != nil {
      fmt.Printf("Error loading [%s]: %s", id, err.Error())
      continue
    }
    names = append(names, *name)
  }

  // wait for cache expiration and we'll see a cache miss
  fmt.Printf("-------------- waiting cache expiration --------------\n\n")

  time.Sleep(ttl)

  for i := 0; i < 5; i++ {
    name, err := repo.DoAnExpensiveQuery(id)
    if err != nil {
      fmt.Printf("Error loading [%s]: %s", id, err.Error())
      continue
    }
    names = append(names, *name)
  }

  fmt.Println("Result:", names)
}

It prints:

Cache miss for id: 2c1b7cd2-0420-4b73-a3f9-734504842fb9

Cache hit for id: 2c1b7cd2-0420-4b73-a3f9-734504842fb9

Cache hit for id: 2c1b7cd2-0420-4b73-a3f9-734504842fb9

Cache hit for id: 2c1b7cd2-0420-4b73-a3f9-734504842fb9

Cache hit for id: 2c1b7cd2-0420-4b73-a3f9-734504842fb9

-------------- waiting cache expiration --------------

Cache miss for id: 2c1b7cd2-0420-4b73-a3f9-734504842fb9

Cache hit for id: 2c1b7cd2-0420-4b73-a3f9-734504842fb9

Cache hit for id: 2c1b7cd2-0420-4b73-a3f9-734504842fb9

Cache hit for id: 2c1b7cd2-0420-4b73-a3f9-734504842fb9

Cache hit for id: 2c1b7cd2-0420-4b73-a3f9-734504842fb9

Result: [Husni Husni Husni Husni Husni Husni Husni Husni Husni Husni]

At the first hit, since we don't have a cached version of the data, it hits the database, and subsequent calls will hit the cache layer.

All code above is hosted on GitHub. I added some additional logs to simulate the latency.

You can browse the code or run the simulation here.

Cache stampede problem

There is another beast to tame when you're working on cache-aside pattern, it's the cache stampede problem. If we quote it from Wikipedia, it says:

A cache stampede is a type of cascading failure that can occur when massively parallel computing systems with caching mechanisms come under a very high load. This behaviour is sometimes also called dog-piling.

View on Wikipedia>

So, for a real world example, let's say we have an e-commerce site, and we're sending some promotions directly via push notification. It means that most of our users are clicking the notification on their phone directly at the same time.

Let's say we'll have 1000 users opening the app at the same time, at the same second. Just a little time prior to the traffic burst, our cache layer is on a cold state, it means that some of the cached data are already expired. In this scenario all sudden traffic is likely hitting the database directly -- cache miss. The database is under very high load at this time.

Our code above does not withstand the cache stampede when we're simulating parallel execution.

Let's change the code to simulate parallel execution.

import (
  // ............
  "sync"
  // ............
)

func main() {
  // ............
  // ............

  id := "2c1b7cd2-0420-4b73-a3f9-734504842fb9"

  var wg sync.WaitGroup
  wg.Add(5)
  var names []string
  for i := 0; i < 5; i++ {
    go func(id string) {
      defer wg.Done()
      name, err := redisRepository.DoAnExpensiveQuery(id)
      if err != nil {
        fmt.Printf("Error loading [%s]: %s", id, err.Error())
        return
      }
      names = append(names, *name)
    }(id)
  }
  wg.Wait()

  fmt.Println("Result:", names)
}

It prints:

Cache miss for id: 2c1b7cd2-0420-4b73-a3f9-734504842fb9
Cache miss for id: 2c1b7cd2-0420-4b73-a3f9-734504842fb9
Cache miss for id: 2c1b7cd2-0420-4b73-a3f9-734504842fb9
Cache miss for id: 2c1b7cd2-0420-4b73-a3f9-734504842fb9
Cache miss for id: 2c1b7cd2-0420-4b73-a3f9-734504842fb9

Result: [Husni Husni Husni Husni Husni]

You can browse the code or run the simulation here.

As you can see, all of them is cache miss. Our MySQL database is now working hard to serve all the same data. So how can we solve it?

There are some different ways to handle this problem, I'll cover it in the next posts.

I hope this article is clear enough and easy to digest. If you have some feedbacks, let me know in the comment section below.

Cover image: Tyler Daviaux on Unsplash

Dev.to Editor Kitchen Sink

Husni Adil Makmur — Thu, 10 Dec 2020 08:02:35 +0000

Learn More: https://dev.to/p/editor_guide

Markdown

Bold & Italic

Code	Renders
`double asterisks or __double underscores__`	double asterisks or double underscores
`asterisks or _underscores_`	asterisks or underscores

Links

Code	Renders
`[I'm an inline link](https://dev.to)`	I'm an inline link
`<a name="anchored">Anchored links</a>`	Anchored links

Code:

## Table Of Contents
  * [Chapter 1](#chapter-1)
  * [Chapter 2](#chapter-2)

### Chapter 1 <a name="chapter-1"></a>

Renders:

Chapter 1
Chapter 2

Chapter 1 Inline Images

Code:

![example image, with sloan](https://res.cloudinary.com/practicaldev/image/fetch/s--OsLaFSo9--/c_fill,f_auto,fl_progressive,h_220,q_auto,w_220/https://thepracticaldev.s3.amazonaws.com/uploads/user/profile_image/31047/af153cd6-9994-4a68-83f4-8ddf3e13f0bf.jpg)

Renders:

Code:

<figcaption> You can even add a caption using the HTML <code>figcaption</code> tag!</figcaption>

Renders:

You can even add a caption using the HTML figcaption tag!

Headers

Code:

# One '#' for a h1 header
## Two '#'s for a h2 header
### Three '#'s for a h3 header
#### Four '#'s for a h4 header
##### Five '#'s for a h5 header
###### Six '#'s for a h6 header

Renders:

One '#' for a h1 header

Two '#'s for a h2 header

Three '#'s for a h3 header

Four '#'s for a h4 header

Five '#'s for a h5 header

Six '#'s for a h6 header

Author Notes/Comments

Code: 

Renders:

🌊 Liquid Tags

DEV Article/Post Embed

Code: {% https://dev.to/thepracticaldev/welcome-thread-v103-4dap %}

Renders:

Welcome Thread - v103

dev.to staff ・ Dec 9 '20 ・ 1 min read

#welcome

Code: {% link thepracticaldev/welcome-thread-v103-4dap %}

Renders:

Welcome Thread - v103

dev.to staff ・ Dec 9 '20 ・ 1 min read

#welcome

Code: {% post https://dev.to/thepracticaldev/welcome-thread-v103-4dap %}

Renders:

Welcome Thread - v103

dev.to staff ・ Dec 9 '20 ・ 1 min read

#welcome

Code: {% post thepracticaldev/welcome-thread-v103-4dap %}

Renders:

Welcome Thread - v103

dev.to staff ・ Dec 9 '20 ・ 1 min read

#welcome

DEV User Embed

Code: {% user thepracticaldev %}

Renders:

dev.to staffFollow

The hardworking team behind dev.to ❤️

DEV Tag Embed

Code: {% tag git %}

Renders:

#git Follow

Software for tracking changes in any set of files, usually used for coordinating work among programmers collaboratively developing source code during software development.

DEV Comment Embed

Code: {% comment 18nkn %}

Renders:

Husni Adil Makmur • Dec 6 '20

I didn't know that this is a community powered site until I saw the Sign Up button and registered.

DEV Podcast Episode Embed

Code: {% podcast https://dev.to/syntax/react-hooks %}

Renders:

React Hooks

Syntax - Tasty Web Development Treats

Your browser does not support the audio element.

1x initializing... ×

DEV Listing Embed

Code: {% listing https://dev.to/listings/education/learn-typescript-this-weekend-free-video-course-258o %}

Renders:

This listing has expired.

Code: {% listing education/learn-typescript-this-weekend-free-video-course-258o %}

Renders:

This listing has expired.

Details Embed

Code: {% details summary %} content {% enddetails %}

Renders: summary

content

Code: {% spoiler summary %} content {% endspoiler %}

Renders: summary

content

Code: {% collapsible summary %} content {% endcollapsible %}

Renders: summary

content

Twitter Embed

Code: {% twitter 834439977220112384 %}

Renders:

The Practical Dev

@thepracticaldev

‌‌
As promised— FREE STICKERS FOR ALL

dev.to/freestickers
‌‌

16:29 PM - 22 Feb 2017

Twitter Timeline

Code: {% twitter_timeline https://twitter.com/NYTNow/timelines/576828964162965504 %}

Renders:

View on Twitter

Glitch embed

Code: {% glitch earthy-course %}

Renders:

GitHub Repo Embed

Code: {% github forem/forem %}

Renders:

forem / forem

For empowering community 🌱

Forem 🌱

For Empowering Community

Welcome to the Forem codebase, the platform that powers dev.to. We are so excited to have you. With your help, we can build out Forem’s usability, scalability, and stability to better serve our communities.

What is Forem?

Forem is open source software for building communities. Communities for your peers, customers, fanbases, families, friends, and any other time and space where people need to come together to be part of a collective See our announcement post for a high-level overview of what Forem is.

dev.to (or just DEV) is hosted by Forem. It is a community of software developers who write articles, take part in discussions, and build their professional profiles. We value supportive and constructive dialogue in the pursuit of great code and career growth for all members. The ecosystem spans from beginner to advanced developers, and all are welcome to find their place…

View on GitHub

Code: {% github forem/forem no-readme %}

Renders:

forem / forem

For empowering community 🌱

GitHub Issue, Pull request or Comment Embed

Code: {% github https://github.com/forem/forem/issues/9 %}

Renders:

Interactive code snippets #9

viebel posted on Dec 15, 2016

Dev.to looks awesome. Congrats!

I was thinking of an integration of the klipse plugin into dev.to to allow blog writers to have interactive code snippets in javascript, ruby, python, scheme or ocaml.

And write cool blog posts like:

What do you say?

View on GitHub

GitHub Gist Embed

Code: {% gist https://gist.github.com/CristinaSolana/1885435 %}

Renders:

Code: {% gist https://gist.github.com/CristinaSolana/1885435 file=gistfile1.md %}

Renders:

Code: {% gist https://gist.github.com/suntong/3a31faf8129d3d7a380122d5a6d48ff6/f77d01e82defbf736ebf4879a812cf9c916a9252 %}

Renders:

Code: {% gist https://gist.github.com/suntong/3a31faf8129d3d7a380122d5a6d48ff6/f77d01e82defbf736ebf4879a812cf9c916a9252 file=Images.tmpl %}

Renders:

GitPitch Embed

Code: {% gitpitch https://gitpitch.com/gitpitch/in-60-seconds %}

Renders:

Video Embed

Code: {% youtube dQw4w9WgXcQ %}

Renders:

Code: {% vimeo 193110695 %}

Renders:

Code: {% twitch ClumsyPrettiestOilLitFam %}

Renders:

Medium Embed

Code: {% medium https://medium.com/s/story/boba-science-how-can-i-drink-a-bubble-tea-to-ensure-that-i-dont-finish-the-tea-before-the-bobas-7fc5fd0e442d %}

Renders:

How Can I Drink Bubble Tea Without Finishing the Tea Before the Bobas? | by Krist Wongsuphasawat | Medium

Krist Wongsuphasawat ・ Oct 16, 2018 ・
Medium

SlideShare Embed

Code: {% slideshare d5rGkEgXFDRN17 %}

Renders:

CodePen Embed

Code: {% codepen https://codepen.io/twhite96/pen/XKqrJX %}
default-tab

Renders default-tab

Code: {% codepen https://codepen.io/twhite96/pen/XKqrJX default-tab=js,result %}

Renders:

Kotlin Playground

Code: {% kotlin https://pl.kotl.in/owreUFFUG?theme=darcula&from=3&to=6&readOnly=true %}

Renders:

RunKit Embed

Code:

{% runkit
// hidden setup JavaScript code goes in this preamble area
const hiddenVar = 42
%}
// visible, reader-editable JavaScript code goes here
console.log(hiddenVar)
{% endrunkit %}

Renders:


    
// hidden setup JavaScript code goes in this preamble area
const hiddenVar = 42


    
// visible, reader-editable JavaScript code goes here
console.log(hiddenVar)

KaTeX Embed

Code:

{% katex %}
 c = \pm\sqrt{a^2 + b^2}
{% endkatex %}

Renders:

\pm\sqrt{a^2 + b^2}

Code:

{% katex inline %}
 c = \pm\sqrt{a^2 + b^2}
{% endkatex %}

Renders:

$\pm\sqrt{a^2 + b^2}$

Stackblitz Embed

Code: {% stackblitz ball-demo %}

Renders:

Code: {% stackblitz ball-demo view=preview %}

Renders:

Code: {% stackblitz ball-demo file=style.css %}

Renders:

CodeSandbox Embed

Code: {% codesandbox ppxnl191zx %}

Renders:

Code: {% codesandbox ppxnl191zx initialpath=/initial/load/path %}

Renders:

Code: {% codesandbox ppxnl191zx module=/path/to/module %}

Renders:

Code: {% codesandbox ppxnl191zx runonclick=1 %}

Renders:

JSFiddle Embed

Code: {% jsfiddle https://jsfiddle.net/link2twenty/v2kx9jcd %}

Renders:

Code: {% jsfiddle https://jsfiddle.net/webdevem/Q8KVC result,html,css %}

Renders:

JSitor Liquid Tag

Code: {% jsitor https://jsitor.com/embed/B7FQ5tHbY %}

Renders:

Code: {% jsitor https://jsitor.com/embed/B7FQ5tHbY?html&js&css&result&light %}

Renders:

Code: {% jsitor B7FQ5tHbY %}

Renders:

Code: {% jsitor B7FQ5tHbY?html&js&css&result&light %}

Renders:

repl.it Embed

Code: {% replit @WigWog/PositiveFineOpensource %}

Renders:

Stackery Embed

Code: {% stackery deeheber lambda-layer-example master %}

Renders:

Next Tech Embed

Renders:

Code: {% nexttech https://nt.dev/s/6ba1fffbd09e %}

Renders:

Instagram Embed

Code: {% instagram BXgGcAUjM39 %}

Renders:

Speakerdeck Tag

Code:

# Given this embed link:
<script async class="speakerdeck-embed"
    data-id="7e9f8c0fa0c949bd8025457181913fd0"
    data-ratio="1.77777777777778" src="//speakerdeck.com/assets/embed.js"></script>
{% speakerdeck 7e9f8c0fa0c949bd8025457181913fd0 %}

Renders:

Soundcloud Embed

Code: {% soundcloud https://soundcloud.com/jabs-badut/iwan-fals-kesaksian %}

Renders:

Spotify Embed

Code: {% spotify spotify:album:4RuzGKLG99XctuBMBkFFOC %}

Renders:

Blogcast Tag

Code: {% blogcast 1234 %}

Renders:

Parler Tag

Code: {% parler https://www.parler.io/audio/73240183203/ab59b90c45cd1f2144291f1a1cfd69894f87aabf.e466ec75-50e8-47c9-b376-55122f2e3a08.mp3 %}

Renders:

Stack Exchange / Stack Overflow Tag

Code: {% stackoverflow 24789130 %}

Renders:

Jul 16 '14 Comments: 1 Answers: 1

I'm testing a gem that outputs color in the terminal:

module Color
    def self.colorize(text, color_code)
        "#{color_code}#{text}e[0m"
    end

    def self.red(text)
        self.colorize(text, "\033[1;31;12m")
    end
end

I have a testing file in the same directory, called color_test.rb:

require_relative 'color.rb'

puts Color.red('I should be red')

This results in the following:

$ ruby color_test.rb
I

…

Open Full Question

Code: {% stackexchange 169988 diy %}

Renders:

Jul 27 '19 Comments: 2 Answers: 3

I have a wine refrigerator that has shelves for wine bottles - image on this question.

I want to use this refrigerator and its shelves as a regular refrigerator. So I need to put something on the shelf to make it flat so it can hold anything. The inner (usable)…

Open Full Question

Code: {% stackexchange 170185 diy %}

Renders:

Jul 30 '19

What about an aluminum baking sheet pan? They come in sizes VERY close to what you want and are easily cleaned.

Example of a close size: https://www.amazon.com/Winware-ALXP-1622-16-Inch-22-Inch-Aluminum/dp/B001CIEJQU

Open Full Answer

Wikipedia Embed

Code: {% wikipedia https://en.wikipedia.org/wiki/Wikipedia %}

Renders:

Wikipedia is a multilingual free online encyclopedia written and maintained by a community of volunteers through open collaboration and a wiki-based editing system. Individual contributors, also called editors, are known as Wikipedians. Wikipedia is the largest and most-read reference work in history. It is consistently one of the 15 most popular websites ranked by Alexa; as of 2022, Wikipedia was ranked the 10th most popular site. It is hosted by the Wikimedia Foundation, an American non-profit organization funded mainly through donations.

View on Wikipedia

Code: {% wikipedia https://en.wikipedia.org/wiki/Wikipedia#Diversity %}

Renders:

Several studies have shown that most Wikipedia contributors are male. Notably, the results of a Wikimedia Foundation survey in 2008 showed that only 13 percent of Wikipedia editors were female.[134] Because of this, universities throughout the United States tried to encourage women to become Wikipedia contributors. Similarly, many of these universities, including Yale and Brown, gave college credit to students who create or edit an article relating to women in science or technology.[135] Andrew Lih, a professor and scientist, wrote in The New York Times that the reason he thought the number of male contributors outnumbered the number of females so greatly was because identifying as a woman may expose oneself to "ugly, intimidating behavior".[136] Data has shown that Africans are underrepresented among Wikipedia editors.[137]

View on Wikipedia

Asciinema Embed

Code: {% asciinema 239367 %}

Renders:

Code: {% asciinema https://asciinema.org/a/239367 %}

Renders:

Reddit Tag

Code: {% reddit https://www.reddit.com/r/aww/comments/ag3s4b/ive_waited_28_years_to_finally_havr_my_first_pet %}

Renders:

I've waited 28 years to finally havr my first pet. Everyone, meet Mycroft.

Jan 15 '19 Author: Miaogua007

See Full Post

Learn More: https://dev.to/p/editor_guide

DEV Community: Husni Adil Makmur

Cache-Aside Pattern

Introduction

Cached data lifetime

Data eviction policies

In-memory cache vs external cache

Using In-memory cache

Pros

Cons

Using external cache

Pros

Cons

When to use

Caching static data

Cache-aside pattern in Go

Cache stampede problem

Dev.to Editor Kitchen Sink

Markdown

Bold & Italic

Links

Table Of Contents

Chapter 1

Inline Images

Headers

One '#' for a h1 header

Two '#'s for a h2 header

Three '#'s for a h3 header

Four '#'s for a h4 header

Five '#'s for a h5 header

Six '#'s for a h6 header

Author Notes/Comments

🌊 Liquid Tags

DEV Article/Post Embed

Welcome Thread - v103

dev.to staff ・ Dec 9 '20 ・ 1 min read

Welcome Thread - v103

dev.to staff ・ Dec 9 '20 ・ 1 min read

Welcome Thread - v103

dev.to staff ・ Dec 9 '20 ・ 1 min read

Welcome Thread - v103

dev.to staff ・ Dec 9 '20 ・ 1 min read

DEV User Embed

dev.to staffFollow

DEV Tag Embed

#git Follow

DEV Comment Embed

DEV Podcast Episode Embed

React Hooks

Syntax - Tasty Web Development Treats

DEV Listing Embed

This listing has expired.

This listing has expired.

Details Embed

Twitter Embed

Twitter Timeline

Glitch embed

GitHub Repo Embed

forem / forem

For empowering community 🌱

Forem 🌱

What is Forem?

forem / forem

For empowering community 🌱

GitHub Issue, Pull request or Comment Embed

Interactive code snippets #9

GitHub Gist Embed

GitPitch Embed

Video Embed

Medium Embed

How Can I Drink Bubble Tea Without Finishing the Tea Before the Bobas? | by Krist Wongsuphasawat | Medium

Krist Wongsuphasawat ・ Oct 16, 2018 ・ Medium

SlideShare Embed

CodePen Embed

Kotlin Playground

RunKit Embed

KaTeX Embed

Stackblitz Embed

CodeSandbox Embed

JSFiddle Embed

JSitor Liquid Tag

Krist Wongsuphasawat ・ Oct 16, 2018 ・
Medium