fullstackpython.com/caching.html at patch-1 · nullism/fullstackpython.com · GitHub

History

238 lines (237 loc) · 19.1 KB

Raw

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

<!DOCTYPE html>

<head>

<title>Caching - Full Stack Python</title>

<!--[if lt IE 9]>

<![endif]-->

</head>

<body>

<h2 style="color: #fff; margin: 20px 40px 0 0;"><a href="https://www.gumroad.com/l/python-deployments" style="color: #fff">The Full Stack Python Guide to Deployments book</a> has been released!</h2>

</div>

</div> <a href="https://github.com/makaimc/fullstackpython.com"><img style="position: absolute; top: 0; right: 0; border: 0;" src="/theme/img/fork.png" alt="Fork me on GitHub"></a>

<span class="logo-title"><a href="/">Full Stack Python</a></span>

</div>

</div><div class="row">

<h1>Caching</h1>

<p>Caching can reduce the load on servers by storing the results of common

operations and serving the precomputed answers to clients. </p>

<p>For example, instead of retrieving data from database tables that rarely

change, you can store the values in-memory. Retrieving values from an

in-memory location is far faster than retrieving them from a database (which

stores them on a persistent disk like a hard drive.) When the cached values

change the system can invalidate the cache and re-retrieve the updated values

for future requests.</p>

<p>A cache can be created for multiple layers of the stack. </p>

<h2>Caching backends</h2>

<ul>

<li>

<p><a href="http://memcached.org/">memcached</a> is a common in-memory caching system.</p>

</li>

<li>

<p><a href="http://redis.io/">Redis</a> is a key-value in-memory data store that can

easily be configured for caching with libraries such as

<a href="https://github.com/sebleier/django-redis-cache">django-redis-cache</a>.</p>

</li>

</ul>

<h2>Caching resources</h2>

<ul>

<li>

<p>"<a href="https://bjornjohansen.no/caching-varnish-or-nginx">Caching: Varnish or Nginx?</a>"

reviews some considerations such as SSL and SPDY support when choosing

reverse proxy Nginx or Varnish.</p>

</li>

<li>

<p><a href="http://bizcoder.com/caching-is-hard-draw-me-a-picture">Caching is Hard, Draw me a Picture</a>

has diagrams of how web request caching layers work. The post is relevant

reading even though the author is describing his Microsoft code as the

impetus for writing the content.</p>

</li>

<li>

<p>While caching is a useful technique in many situations, it's important

to also note that there are

<a href="https://msol.io/blog/tech/2015/09/05/youre-probably-wrong-about-caching/">downsides to caching</a>

that many developers fail to take into consideration.</p>

</li>

</ul>

<h2>Caching learning checklist</h2>

<ol>

<li>

<p>Analyze your web application for the slowest parts. It's likely there are

complex database queries that can be precomputed and stored in an in-memory

data store.</p>

</li>

<li>

<p>Leverage your existing in-memory data store already used for session data

to cache the results of those complex database queries. A

<a href="/task-queues.html">task queue</a> can often be used to precompute the results

on a regular basis and save them in the data store.</p>

</li>

<li>

<p>Incorporate a cache invalidation scheme so the precomputed results remain

accurate when served up to the user.</p>

</li>

</ol>

<h3>What do you want to learn next for your deployment?</h3>

<p class="under-btn">How do I execute code outside the HTTP request-response cycle?</p> </div>

</div>

<p class="under-btn">I want to learn more about app users via web analytics.</p> </div>

</div>

<p class="under-btn">What can I do to mitigate security vulnerability in my web app?</p> </div>

</div>

</div><div id="mc_embed_signup">

<h4>Sign up here to receive an email with major updates to this site and Python tutorials delivered to your inbox once a month.</h4>

</div>

</div>

</form>

</div>

<p style="font-size: .8em; margin-top: 10px;">Searching for a complete, step-by-step deployment walkthrough? Learn more about <a href="http://www.deploypython.com/">The Full Stack Python Guide to Deployments book</a>.

</p>

</div>

</div> <div class="panel panel-success">

<h3 class="panel-head"><a href="/table-of-contents.html" style="color: #fff;">Table of Contents</a></h3>

</div>

<a href="/introduction.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Introduction</a>

<a href="/learning-programming.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Learning Programming</a>

<a href="/why-use-python.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Why Use Python?</a>

<a href="/python-2-or-3.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Python 2 or 3?</a>

<a href="/enterprise-python.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Enterprise Python</a>

<a href="/best-python-resources.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Best Python Resources</a>

<a href="/best-python-videos.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Best Python Videos</a>

<a href="/development-environments.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Development Environments</a>

<a href="/emacs.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Emacs</a>

<a href="/generators.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Generators</a>

<a href="/comprehensions.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Comprehensions</a>

<a href="/web-frameworks.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Web Frameworks</a>

<a href="/django.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Django</a>

<a href="/flask.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Flask</a>

<a href="/bottle.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Bottle</a>

<a href="/pyramid.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Pyramid</a>

<a href="/morepath.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Morepath</a>

<a href="/other-web-frameworks.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Other Web Frameworks</a>

<a href="/web-design.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Web Design</a>

<a href="/cascading-style-sheets.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Cascading Style Sheets</a>

<a href="/javascript.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>JavaScript</a>

<a href="/websockets.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>WebSockets</a>

<a href="/web-application-security.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Web Application Security</a>

<a href="/static-site-generator.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Static Site Generators</a>

<a href="/databases.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Databases</a>

<a href="/no-sql-datastore.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>NoSQL Data Stores</a>

<a href="/object-relational-mappers-orms.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Object-relational Mappers (ORMs)</a>

<a href="/application-programming-interfaces.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Application Programming Interfaces</a>

<a href="/api-integration.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>API Integration</a>

<a href="/api-creation.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>API Creation</a>

<a href="/deployment.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Deployment</a>

<a href="/servers.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Servers</a>

<a href="/platform-as-a-service.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Platform-as-a-service</a>

<a href="/operating-systems.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Operating Systems</a>

<a href="/web-servers.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Web Servers</a>

<a href="/wsgi-servers.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>WSGI Servers</a>

<a href="/source-control.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Source Control</a>

<a href="/application-dependencies.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Application Dependencies</a>

<a href="/static-content.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Static Content</a>

<a href="/task-queues.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Task Queues</a>

<a href="/configuration-management.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Configuration Management</a>

<a href="/continuous-integration.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Continuous Integration</a>

<a href="/logging.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Logging</a>

<a href="/monitoring.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Monitoring</a>

<a href="/web-analytics.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Web Analytics</a>

<a href="/docker.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Docker</a>

<a href="/caching.html" class="list-group-item smaller-item active" style='font-family: "Helvetica Neue",sans-serif;'>Caching</a>

<a href="/microservices.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Microservices</a>

<a href="/testing.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Testing</a>

<a href="/unit-testing.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Unit Testing</a>

<a href="/integration-testing.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Integration Testing</a>

<a href="/code-metrics.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Code Metrics</a>

<a href="/debugging.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Debugging</a>

<a href="/what-full-stack-means.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>What "Full Stack" Means</a>

<a href="/change-log.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Change Log</a>

<a href="/future-directions.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>Future Directions</a>

<a href="/about-author.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>About the Author</a>

</div>

</p>

</div>

</div> <div class="panel panel-success">

<div class="panel-heading"><h3 class="panel-head">Caching</h3></div>

Major updates are tweeted via

<a href="https://twitter.com/fullstackpython">@fullstackpython</a>.

<hr/>

Need more detailed tutorials than you see here?

<a href="http://www.deploypython.com/">Learn more about The Full Stack Python Guide to Deployments book.</a>

</div>

</div></div>

<hr/>

</div>

<a href="http://www.mattmakai.com/" class="underline">Matt Makai</a>

2015

</div>

(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){

(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),

m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)

})(window,document,'script','//www.google-analytics.com/analytics.js','ga');

ga('create', 'UA-19910497-7', 'auto');

ga('send', 'pageview');

</script>

var trackOutboundLink = function(url) { ga('send', 'event', 'outbound', 'click', url, {'hitCallback': function () { document.location = url; } }); }

</script>

</body>

</html>

fullstackpython.com/caching.html at patch-1 · nullism/fullstackpython.com · GitHub

Expand file tree

Breadcrumbs

caching.html

Latest commit

History

Breadcrumbs

caching.html

File metadata and controls