WTF Is Big O Notation?
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WTF Is Big O Notation?
1–10 of 101 posts
Re: WTF Is Big O Notation?
#2A precise way of being imprecise.
Re: WTF Is Big O Notation?
#3My experience, as someone who isn't a professional full-time developer (systems engineer / devops focused), but who personally geeks out on CS theory, is I find it fairly rare for developers that I work with that think of Big O considerations when writing their code.
A prime example, was a piece of code that has to process incoming results that get stuck in a transnational database table. Instead of selecting, then processing, the records that the module cares about, it does the selection (which typically returns 1 - 10 records), sorts them, processes the record from the top of the list, then throws the rest of the initial select results away. It then goes back to the DB an does the same select, and repeats the process.
End result: if the queue gets backed up to 100, or 1000 records, the process never catches up. You have to temporarily change the status of the inbound records to something else, then put maybe 10 at a time back to pending.
There are countless other times I've seen similar types of issues where on small data sets the code runs fine, but the performance degrades to n^2, or even worse is when it degrades in a factorial manor. And the worst of it is that if I talk to the developers using common CS notation (such as, your algorithm should have logarithmic or at worse linear degradation as the input queue grows, and it is behaving exponentially), their eyes glaze over.
Re: WTF Is Big O Notation?
#4The formal definition is a fairly gentle introduction to logical math. Here is a decent enough write-up: https://justin.abrah.ms/computer-science/understanding-big-o...
Re: WTF Is Big O Notation?
#5My experience, as someone who isn't a professional full-time developer (systems engineer / devops focused), but who personally geeks out on CS theory, is I find it fairly rare for developers that I work with that think of Big O considerations when writing their code. A prime example, was a piece of code that has to process incoming results that get stuck in a transnational database table. Instead of selecting, then p…
That's not my experience as a software engineer at all. In fact, I would say that I see people worrying about writing algorithms that are asymptotically optimal (well before that should ever be a consideration) 10x as often as I see people failing to consider the efficiency of the algorithms they write.
Re: WTF Is Big O Notation?
#6My experience, as someone who isn't a professional full-time developer (systems engineer / devops focused), but who personally geeks out on CS theory, is I find it fairly rare for developers that I work with that think of Big O considerations when writing their code. A prime example, was a piece of code that has to process incoming results that get stuck in a transnational database table. Instead of selecting, then p…
One of the things I like about the C++ STL is once you learn the idioms, the API tells you whether an operation is "fast." I don't really care if a line programmer can give me the formal definition of O(x), but I sure want him to know if an operation is appropriate to call in a loop.
That's speaking as a professional. As someone who finds CS fascinating, I'm appalled by the lack of interest many professional developers have in what is one of the most rigorous and elegant fields of mathematical inquiry. Even so I don't expect others to care about the things I do.
Re: WTF Is Big O Notation?
#7My experience, as someone who isn't a professional full-time developer (systems engineer / devops focused), but who personally geeks out on CS theory, is I find it fairly rare for developers that I work with that think of Big O considerations when writing their code. A prime example, was a piece of code that has to process incoming results that get stuck in a transnational database table. Instead of selecting, then p…
The example you gave is not really a Big O issue. It's the extra DB calls adding a huge constant that's the problem not the underlying algorithm. O(x) can be horrible when the constant is 1/10th of a second each record.
This may be a case of the developers not understanding your ORM tooling. They get something that works, and don't quite what's going on under the hood.
Re: WTF Is Big O Notation?
#8My experience, as someone who isn't a professional full-time developer (systems engineer / devops focused), but who personally geeks out on CS theory, is I find it fairly rare for developers that I work with that think of Big O considerations when writing their code. A prime example, was a piece of code that has to process incoming results that get stuck in a transnational database table. Instead of selecting, then p…
> I find it fairly rare for developers that I work with that think of Big O considerations when writing their code
Do you not hear people talk about 'accidentally quadratic' quite a bit? I hear practising developers talk about that a lot. They seem to have a good idea of what to avoid.
Re: WTF Is Big O Notation?
#9That was a good write up, and it will help people. I come from the self taught side, and find that it is critical to know these things when you work in certain areas of a code base and once you reach a certain level. But I don't expect everyone needs to have the same level of understanding.
I also find interviewers asking detailed questions about Big O and specific different algorithms just idiotic, especially the esoteric ones I've been asked in the past and/or heard asked. When I interview someone, all I want to know is that you know there is a difference and know to look when it matters.
My method for learning if a candidate understands this all is to get people to choose data structures based upon different problem sets I will give them and then ask the pros and cons. The more questions they ask about usage usually the more they understand in my experience. And this is just way more informative as a hiring manager as you will learn more if they understand what they are saying, versus if they can regurgitate something they memorized from a book or website.
Re: WTF Is Big O Notation?
#10My experience, as someone who isn't a professional full-time developer (systems engineer / devops focused), but who personally geeks out on CS theory, is I find it fairly rare for developers that I work with that think of Big O considerations when writing their code. A prime example, was a piece of code that has to process incoming results that get stuck in a transnational database table. Instead of selecting, then p…
> I find it fairly rare for developers that I work with that think of Big O considerations when writing their code Do you not hear people talk about 'accidentally quadratic' quite a bit? I hear practising developers talk about that a lot. They seem to have a good idea of what to avoid.
'Accidentally quadratic' happens and is talked about precisely because much of the time, there's not much reason to think about Big O in many practical software development situations.