It’s not just about being the fastest…

First published on Performance Calendar on 21st December 2013

I have been doing a lot of work this year about creating a performance culture within a company. This is an essential step on the route to creating good performance in your products and only when you start treating performance as a first class citizen will you start to get buy in to the time and effort needed to create performant systems, both from the developers and from the business as a whole.

This is a costly process and requires an investment of time and effort from a company to fully implement and the business will expect to see benefits back in return for this investment.

I would like to address two common problems that cause the value of this investment to be undermined.

1) Solving the technical challenge not the business problem

When I have talked to some developers who are getting into performance and trying to get buy in from their business and are struggling I often hear the same complaint – “why don’t they realise that they want as fast a website as possible?”.

To this I always answer – “because they don’t!”. The business in question does not want a fast website. The business wants to make as much money as possible. Only if having a fast website is a vehicle for them doing that do they want a fast website.

The key point I am making here is that it is easy as a techie to get excited by the challenge of setting arbitrary targets and putting time and effort into continually bettering them when more business benefit could be gained from solving other performance problems.

To address this we need to take a step back and address exactly the performance problems that are being seen and how they are impacting the business.

These may be slow page load when not under load. Equally likely will be that they suffer slowdowns under adverse conditions, they suffer intermittent slowdowns under normal load, they use excessive resources on the server necessitating an excessively large platform or many other potential problems.

All of these examples can be boiled down to a direct financial impact on the business.

As an example, one company we worked with determined that their intermittent slowdowns cost them 350 sales on average which would work out to £3.36m per year. This gives you instant business buy in to solve the problem, a direct problem for developers to work on and a trackable KPI to track achievement and know when you are done after which you can move on to the next performance problem.

Another company I worked with had a system that performed perfectly adequately but was very memory hungry. Their business objective was to release some of the memory being used by the servers to be used on alternative projects (i.e. reduce the hosting cost for the application). Again a direct business case, a problem developers can get their teeth into and a trackable KPI.

To sum up – start your performance optimisation with a business impact, put it into financial terms and provide the means to justify the value of the development efforts to the business.

2) Over optimisation results in technical debt

The second issue I would like to address is the idea that we should always build the most ultra performant system.

No – we should always build an APPROPRIATELY performant system.

Over optimising a system can be just as negative as under-optimising. Building a ultra performant, scalable web application takes many factors such as…

Time

Building highly performant systems just takes longer

Complexity

Highly optimised system tend to have a lot more moving parts. Elements such as caching layers, NoSQL databases, sharded databases, cloned data stores, message queues, remote components, multiple languages, technologies and platforms are things that may be introduced to ensure that your system can scale and remain performant. All these things take management, testing, development expertise and hardware.

Expertise

Building ultra performant website is hard, it takes clever people to devise intelligent solutions, often operating at the limits of the technologies being used. These kind of solutions can lead to areas of your system being unmaintainable by the rest of the team. Some of the worst maintenance situations I have seen have been caused by the introduction of some unnecessarily complicated piece of coding designed to solve a potential performance problem that never materialised.

Investment

These system require financial support in terms of hardware, software and development/testing time and effort to build and support.

Compromises

Solving performance issues often is done at the expenses of good practice or functionality elsewhere. This may be as simple as compromising on the timeliness of data by introducing caching but often maybe accepting architectural compromises or even coding good practice compromises to achieve performance.

Summary

The warning I want to give here is to understand your performance landscape, set your KPIs, define your performance non functional requirements, set performance acceptance targets or whatever method you use to determine how your application is expected to perform.

This action is essential to allow developers to be able to make reasonable assessments of the levels of optimisation that are appropriate to perform on the system they are developing.

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