Welcome!

Industrial IoT Authors: Liz McMillan, Olivier Huynh Van, Pat Romanski, Christopher Harrold, Derek Weeks

Related Topics: Java IoT, Industrial IoT, Microsoft Cloud, Open Source Cloud, IoT User Interface, Apache

Java IoT: Article

Caching: Up and Down the Stack

Boston Web Performance Meetup Wrap-up

The other month I presented Caching Up and Down the Stack at the Boston Web Performance meetup. It was great to get the chance to present to the 60+ people who came out for the talk. Unsurprisingly, many of the people there knew a lot about caching in all of the different levels I touched on, and some great conversation developed.

I covered six of the major areas of caching available to web devs today. On the HTML / JS / CSS side, you can use client asset caches, full-page HTTP caches (like Varnish) and partial template caches. On the back end, you can use generated code caches, manually cache objects in memory or nearby services or even enable your database’s query cache (though, as the audience reminded me, if you’re using MySQL, just don’t. See below for why). Caching at each layer has advantages and disadvantages, and throughout, you’ll only be effective if you know what you’re caching, why you’re caching it and if you measure the improvement of doing so. If you want to know more, check out the slides on Slideshare.

Obviously, this is a huge topic, and I didn’t come anywhere close to doing it justice. The audience came up with several interesting points, both during and afterwards.

1. One of the first questions I got was about a comparison between a cached an uncached page load. I showed this graph:

The main takeaway from this is the drop in bandwidth. 500k isn’t a trivial amount to download, especially when spread over 20-odd files, and doubly so when on a mobile browser. That’s a great improvement when cached, but somebody asked, “Why did the number of requests change?” It turns out that specifying a file as cacheable doesn’t necessarily imply that a connection to the server is unnecessary. For instance, files with an etag header set will validate against the server, and the server will return a 304 Unmodified if the etag matches. On the other hand, if the Cache-Control header is set with “public” and an appropriate max-age directive, the content doesn’t have to be validated, and the browser may entirely eliminate the HTTP request.These days, this can actually be quite effective, as the ratio of time spent downloading content vs. establishing connections is lower than it has ever been. If you’ve got content that doesn’t change (because it’s versioned in the filename, for instance), set it as Cache-Control: public, max-age=large-number!

2. In the words of one wise audience member, “The MySQL query cache sucks. Never use it.” I don’t disagree. But why? Consider the following properties of this cache:

  • It only caches exact matches on queries.
  • It is invalidated every time anything in the table changes.

If you think about your data and access patterns, there’s a good chance one or both of these properties make the MySQL query cache unsuitable for production use. Few apps have large, static data sets and unpredictable but highly repetitive queries. In most cases, the query cache will spend its time in two states – cold and empty, or flushing itself. Neither will make your application appreciably faster.

Instead, consider caching objects at a coarser granularity once you’ve retrieved them from the DB, or consider adding a proper set of indices to ensure that common queries to your tables are quick.

3. Though I spent most of my time on object caching, I neglected to mention one of the most effective places to cache language objects: in memory on the machine it’s used on! Object caching is generally any type of caching that’s done by retrieving an object from a slower data store (that may involve an expensive computation), and storing the result in an easy-to-lookup place. While memcache in great for this, and has the advantage of scaling independently of your app itself, sometimes just stashing an object in a global dictionary can be the best solution. Plus, especially if the set is bounded or never changes, invalidation and cleanup can be as easy as waiting until your next deploy to reboot the app servers!

All in all, it was great to see everybody out, and I’m looking forward to the next Boston Web Performance Meet-up!

Related Articles

The 5 Critical Things You Need to Know to Assure Optimal Performance in the Cloud

QoS, Wherefore Art Thou

Solving Slow Database Performance In Java and MySQL

More Stories By TR Jordan

A veteran of MIT’s Lincoln Labs, TR is a reformed physicist and full-stack hacker – for some limited definition of full stack. After a few years as Software Development Lead with Thermopylae Science and Techology, he left to join Tracelytics as its first engineer. Following Tracelytics merger with AppNeta, TR was tapped to run all of its developer and market evangelism efforts. TR still harbors a not-so-secret love for Matlab-esque graphs and half-baked statistics, as well as elegant and highly-performant code. Read more of his articles at www.appneta.com/blog or visit www.appneta.com.

@ThingsExpo Stories
In this strange new world where more and more power is drawn from business technology, companies are effectively straddling two paths on the road to innovation and transformation into digital enterprises. The first path is the heritage trail – with “legacy” technology forming the background. Here, extant technologies are transformed by core IT teams to provide more API-driven approaches. Legacy systems can restrict companies that are transitioning into digital enterprises. To truly become a lea...
Almost two-thirds of companies either have or soon will have IoT as the backbone of their business in 2016. However, IoT is far more complex than most firms expected. How can you not get trapped in the pitfalls? In his session at @ThingsExpo, Tony Shan, a renowned visionary and thought leader, will introduce a holistic method of IoTification, which is the process of IoTifying the existing technology and business models to adopt and leverage IoT. He will drill down to the components in this fra...
Digital transformation is too big and important for our future success to not understand the rules that apply to it. The first three rules for winning in this age of hyper-digital transformation are: Advantages in speed, analytics and operational tempos must be captured by implementing an optimized information logistics system (OILS) Real-time operational tempos (IT, people and business processes) must be achieved Businesses that can "analyze data and act and with speed" will dominate those t...
If you had a chance to enter on the ground level of the largest e-commerce market in the world – would you? China is the world’s most populated country with the second largest economy and the world’s fastest growing market. It is estimated that by 2018 the Chinese market will be reaching over $30 billion in gaming revenue alone. Admittedly for a foreign company, doing business in China can be challenging. Often changing laws, administrative regulations and the often inscrutable Chinese Interne...
I'm a lonely sensor. I spend all day telling the world how I'm feeling, but none of the other sensors seem to care. I want to be connected. I want to build relationships with other sensors to be more useful for my human. I want my human to understand that when my friends next door are too hot for a while, I'll soon be flaming. And when all my friends go outside without me, I may be left behind. Don't just log my data; use the relationship graph. In his session at @ThingsExpo, Ryan Boyd, Engi...
Internet of @ThingsExpo, taking place November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with the 19th International Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world and ThingsExpo Silicon Valley Call for Papers is now open.
Adobe is changing the world though digital experiences. Adobe helps customers develop and deliver high-impact experiences that differentiate brands, build loyalty, and drive revenue across every screen, including smartphones, computers, tablets and TVs. Adobe content solutions are used daily by millions of companies worldwide-from publishers and broadcasters, to enterprises, marketing agencies and household-name brands. Building on its established design leadership, Adobe enables customers not o...
If you’re responsible for an application that depends on the data or functionality of various IoT endpoints – either sensors or devices – your brand reputation depends on the security, reliability, and compliance of its many integrated parts. If your application fails to deliver the expected business results, your customers and partners won't care if that failure stems from the code you developed or from a component that you integrated. What can you do to ensure that the endpoints work as expect...
Just over a week ago I received a long and loud sustained applause for a presentation I delivered at this year’s Cloud Expo in Santa Clara. I was extremely pleased with the turnout and had some very good conversations with many of the attendees. Over the next few days I had many more meaningful conversations and was not only happy with the results but also learned a few new things. Here is everything I learned in those three days distilled into three short points.
WebRTC adoption has generated a wave of creative uses of communications and collaboration through websites, sales apps, customer care and business applications. As WebRTC has become more mainstream it has evolved to use cases beyond the original peer-to-peer case, which has led to a repeating requirement for interoperability with existing infrastructures. In his session at @ThingsExpo, Graham Holt, Executive Vice President of Daitan Group, will cover implementation examples that have enabled ea...
SYS-CON Events announced today that ReadyTalk, a leading provider of online conferencing and webinar services, has been named Vendor Presentation Sponsor at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. ReadyTalk delivers audio and web conferencing services that inspire collaboration and enable the Future of Work for today’s increasingly digital and mobile workforce. By combining intuitive, innovative tec...
There is growing need for data-driven applications and the need for digital platforms to build these apps. In his session at 19th Cloud Expo, Muddu Sudhakar, VP and GM of Security & IoT at Splunk, will cover different PaaS solutions and Big Data platforms that are available to build applications. In addition, AI and machine learning are creating new requirements that developers need in the building of next-gen apps. The next-generation digital platforms have some of the past platform needs a...
Fifty billion connected devices and still no winning protocols standards. HTTP, WebSockets, MQTT, and CoAP seem to be leading in the IoT protocol race at the moment but many more protocols are getting introduced on a regular basis. Each protocol has its pros and cons depending on the nature of the communications. Does there really need to be only one protocol to rule them all? Of course not. In his session at @ThingsExpo, Chris Matthieu, co-founder and CTO of Octoblu, walk you through how Oct...
Smart Cities are here to stay, but for their promise to be delivered, the data they produce must not be put in new siloes. In his session at @ThingsExpo, Mathias Herberts, Co-founder and CTO of Cityzen Data, will deep dive into best practices that will ensure a successful smart city journey.
Businesses are struggling to manage the information flow and interactions between all of these new devices and things jumping on their network, and the apps and IT systems they control. The data businesses gather is only helpful if they can do something with it. In his session at @ThingsExpo, Chris Witeck, Principal Technology Strategist at Citrix, will discuss how different the impact of IoT will be for large businesses, expanding how IoT will allow large organizations to make their legacy ap...
Major trends and emerging technologies – from virtual reality and IoT, to Big Data and algorithms – are helping organizations innovate in the digital era. However, to create real business value, IT must think beyond the ‘what’ of digital transformation to the ‘how’ to harness emerging trends, innovation and disruption. Architecture is the key that underpins and ties all these efforts together. In the digital age, it’s important to invest in architecture, extend the enterprise footprint to the cl...
SYS-CON Events announced today that Numerex Corp, a leading provider of managed enterprise solutions enabling the Internet of Things (IoT), will exhibit at the 19th International Cloud Expo | @ThingsExpo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Numerex Corp. (NASDAQ:NMRX) is a leading provider of managed enterprise solutions enabling the Internet of Things (IoT). The Company's solutions produce new revenue streams or create operating...
24Notion is full-service global creative digital marketing, technology and lifestyle agency that combines strategic ideas with customized tactical execution. With a broad understand of the art of traditional marketing, new media, communications and social influence, 24Notion uniquely understands how to connect your brand strategy with the right consumer. 24Notion ranked #12 on Corporate Social Responsibility - Book of List.
Why do your mobile transformations need to happen today? Mobile is the strategy that enterprise transformation centers on to drive customer engagement. In his general session at @ThingsExpo, Roger Woods, Director, Mobile Product & Strategy – Adobe Marketing Cloud, covered key IoT and mobile trends that are forcing mobile transformation, key components of a solid mobile strategy and explored how brands are effectively driving mobile change throughout the enterprise.
As ridesharing competitors and enhanced services increase, notable changes are occurring in the transportation model. Despite the cost-effective means and flexibility of ridesharing, both drivers and users will need to be aware of the connected environment and how it will impact the ridesharing experience. In his session at @ThingsExpo, Timothy Evavold, Executive Director Automotive at Covisint, will discuss key challenges and solutions to powering a ride sharing and/or multimodal model in the a...