Sunday, July 2, 2017

A key to the kingdom


Agile talks about emergent architecture and building vertical slices of functionality. It is typically understood that all efforts must go toward creating valuable user-facing pieces, as opposed to delivering software layers that cannot be used until all other layers are in place.  Unfortunately, this approach is often taken as “all we need is the visible parts”, i.e. the parts that the user gets to see and click on, or that push the data to be displayed.

When I first encountered a large DB supporting a well-used, living application with no indexes or foreign keys, I thought it was a rare oversight.  Then I encountered a few more database setups just like it, with large and heavily used tables and relationships, but neither indexes nor keys defined.  In all cases, users were complaining about slow response times, and administrators remembered more than one instance of the application becoming non-responsive under heavy load as DB requests timed out en masse.

Other developers I talked to also mentioned that they worked with reasonably large DBs that were missing indexes and foreign keys. A number of people, working in different companies on unrelated projects, mentioned that their engineering managers or software architects absolutely refused all suggestions to create even primary keys on tables “since nobody sees them anyway”. Several developers talked about applications being re-implemented, in part, because of poor response times caused by frequent timeouts of DB requests.

Vertical slices of user-visible functionality must include “the plumbing” that allows the application to handle the expected load. “Emergent architecture” is not complete without at least basic considerations of technical quality. A project cannot succeed without understanding what it takes to deliver user value in a production situation – and that typically includes multiple users working simultaneously.  Building in proper DB infrastructure is a simple example of such considerations, the work that is not visible but nevertheless valuable to the user.


Friday, June 16, 2017

When the math is off

How Developers Rate Their Own Programming SkillsMax Woolf @minimaxir

Here is a common interview question that is typically gets asked in interviews:
"Please rate yourself in your best skill, on a scale of 1 to 10, where 5 is average."

The answers most often are between 7 and 9.5 inclusive, with an occasional 10.
Lets consider what that means.

Skills and ability to contribute have been shown to be distributed according to a Pareto Principle: 20% of the population possess 80% of the skills and deliver 80% of the results. Suppose, it is a Pareto distribution with the slope of 1, and a minimum skill value of 1. There is no max value for the true Pareto distribution, but the way developers are asked to use the scale, the max value is set at 10.

A few runs on University of Alabama in Huntsville Special Distribution Simulator show that for a 1000-point simulation the mean is in the 7-9 range. So far so good.

However, the randomly generated values have no set maximum, and can go well above 10. Even a few higher values in a large set skew the mean significantly.  To get back to the allowed range of values 1 through 10, replace all values in the 1000-point dataset, that are above maximum allowed value of 10, with 10.5. The average drops down to ~4.  The median is ~2, i.e. half the data points have values of less than 2.

That contradicts the initial question, which sets 5 as being the average.  A distribution of skills is likely to have an average level skewing lower than half the range. In this example of modeling skill distribution with a Pareto distribution 1,1 - way lower, at the mean value of 2.  More importantly, it raises the question on how well the interviewers understand the question they are asking the candidates.

"The best and the rest: Revising the norm of normality of individual performance."
by Ernesto'Boyle Jr., Herman Aguinis

All of the above is just a long way of saying that when a typical candidate for a position rates himself in response to the question, they are, so to speak, gaming the situation.

The more interesting observation is that not only the question is asked regularly, by many, if not most, developers acting in the interviewer capacity. The answer is taken seriously and can influence how the interview proceeds, as well as the outcome. People with higher self-rating (those claiming to be above 8) are more likely to be hired and promoted.


Wednesday, June 7, 2017

Honest or nice


We have a lot of conversations how we could do better. Deliver more functionality and prettier UI, cause fewer bugs, have more fun while we put in more hours.  Write better code, and pay back the technical debt.

At 200OK web professional's conference we were talking about code review – the part of software development process where developers and architects get together to consider other people’s code with the purpose of offering critique.

Having one’s code subject to review is terrifying for many people, and liberating for others.  It is also necessary, for most of the code outside of personal projects.  But how we are going about doing the review can make a huge difference for all involved.

There comes a scary idea of being nice to the people one works with. Genuinely, authentically nice – actually wish them to be successful, be willing to put effort in helping them, and talking about that.
Here are some suggestions:

  • Start code reviews with saying to your fellow developers that the work they have done toward the team’s goal is noticed and appreciated.
  • Call out good code – clearly expressed logic, fitting patterns, relevant abstractions, meaningful naming.   
  • Notice good intentions, as expressed in code, even if the result is less than perfect. That includes error handling, code broken down into smaller modules, attempts at unit tests.  
  • Finally, suggest changes as you would to a very senior, very experienced colleague – share knowledge while acknowledging their wisdom and understanding.  Everyone needs to learn, and everyone deserves to learn in a respectful, cooperative environment. 

Being actively and explicitly nice, yet honest, to one’s teammates does a few interesting things to overall team dynamic. More people speak up and offer ideas. Jerks become more visible. More conflict bubbles up and out, and leads to a healthy discussion.

It may even lead to delivering more value, while enjoying working together more.