Questions related to improving application performance, this can be range from selection software architecture to selection of algorithms.

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When is it a good time to reason about performance in Haskell?

Simon Peyton Jones himself recognizes that reasoning about performance in Haskell is hard due to the non strict semantics. I have yet to write a significant project in haskell so I wonder: can I ...
8
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2answers
638 views

Is there any better approach to shortest path finding within a (vehicular) traffic network?

Dear fellow programmers, We're developing software which simulates vehicular traffic. Part of the process called "assignment" is concerned with assigning vehicles to their routes and has to use some ...
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4answers
12k views

Practical size limits of a Hashtable and Dictionary in c#

What are the practical limits for the number of items a C# 4 Dictionary or Hashtable can contain and the total number of bytes these structures can reasonable contain. I'll be working with large ...
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3answers
14k views

How can I monitor the JVM memory in a proper way?

I'm thinking of how we do JVM memory monitor in a low overhead way in production environment even under busy hour. Suppose I have two tomcat app server in production, load balance set up behind them. ...
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3answers
2k views

What is the best way to keep track of the median?

I read a question, and I'm looking for input on how to solve it: Numbers are randomly generated and stored into an (expanding) array, How would you keep track of the median? There are two data ...
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7answers
1k views

Should I charge a client for mistakes that I made? [duplicate]

After developing a website for a client, I've realized that the load time is too extreme, and some changes need to be made. The extreme load times are attributed to the bloated css/js frameworks that ...
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5answers
1k views

How do you off load work from the database?

In at least the web development field, web servers are everywhere but are backed by very few database servers. As web servers get hit with requests they execute large queries on the database, putting ...
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4answers
3k views

Is it a performance hit to create threads that loop a lot to check for things?

This is a generic question that I've always wondered. In general, is it intensive for a CPU to create threads that perform "while not true ..." loops or similar? For example, suppose I do: // ...
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6answers
4k views

Software Optimization vs. Hardware Optimization - what has the bigger impact?

I was wondering how software optimization and hardware optimization compare when it comes to the impact they have on speed and performance gains of computers. I have heard that improving software ...
7
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3answers
712 views

Enterprise software: Where should the code go? [duplicate]

I recently went for an interview with a software company that claims to write enterprise level software. During the interview, the interviewer remarked that its better to use the database simply to ...
7
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1answer
2k views

Log to file or to database table?

I'm developing a web application which uses MS SQL for various data: including users, user accounts, user licenses, license prices, invoices. I need to log users' real-time usage of the system, and ...
7
votes
2answers
882 views

Does javascript support numerically indexed arrays with a more optimized algorithm than an associative array?

I know that Python, Perl, Java, Lua and obviously C (as it's the only array that's in ANSI standard afaik) support faster looking of numerically indexed arrays than doing a hash lookup or anything ...
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2answers
2k views

Does LINQ require significantly more processing cycles and memory than lower-level data iteration techniques?

Background I am recently in the process of enduring grueling tech interviews for positions that use the .NET stack, some of which include silly questions like this one, and some questions that are ...
7
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4answers
980 views

Is there a performance benefit to using immutable objects in a scripting language?

As I understand it, writing your objects in an immutable style can help the performance of your program for compiled languages, as the compiler tends to rewrite your code in single static assignment ...
7
votes
2answers
401 views

How does the Hip hop virtual machine (HHVM) theoretically improve PHP runtime performance?

From a high level, how does Facebook, et. al use to improve PHP performance with the Hip Hop Virtual Machine? How does it differ from executing code using the traditional zend engine? Is it because ...
7
votes
2answers
271 views

What are the benefits of archiving?

I always see sites that only keeps fresh content on the home or subsections, and the rest of the content is kept in a separate section called 'archive'. Recently I have also heard that NoSQL DB's ...
7
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2answers
9k views

How to design a scalable notification system? [closed]

I need to write a notification system manager. Here is my requirements: I need to be able to send a Notification on different platforms, which may be totally different (for exemple, I need to be ...
7
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2answers
226 views

Are Concurrency Abstractions Emulating UNIX Processes?

OK, I was pondering this today, and I've come to ask for completely subjective and bias opinions on it. Paradoxically, despite this, I don't think it's flame-war fodder either. I think there is room ...
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3answers
1k views

Is it good to define a variable inside a loop? [closed]

My instructor once told me that I should not define a variable inside a loop, but I honestly still do not understand why. What are the disadvantages of that? Could any body explain that to me?
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4answers
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Why scalability issues cannot be solved by more servers ?

I know that big websites suffer from scalability issues and I guess that more servers (hardware) can help to handle scalabililty issues but I see that big websites are stuck about scalability even if ...
6
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2answers
13k views

Low Latency Unix/Linux

Most low latency/high frequency programming jobs (based on job specs) appear to be implemented on unix platforms. In a lot of the specs they make particular request for people with "low latency linux" ...
6
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4answers
5k views

Big-O for nested loop

I am reading this post on Big-O It says that the following code is O(n^2): bool ContainsDuplicates(String[] strings) { for(int i = 0; i < strings.Length; i++) { for(int j = 0; j ...
6
votes
1answer
370 views

Should web browsers include popular web framework libraries?

What reasons are there for web browsers to not have a library of popular web frameworks. For example if a web page included jQuery, why shouldn't the browser have it's own static version, which is ...
6
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3answers
374 views

Fine Line: Readability Vs Speed [duplicate]

Is there a line between readability vs compile or processing speed? Aside from the extreme cases, I wouldn't think it would be even worth saving that little bit extra in favor of legibility... For ...
6
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3answers
15k views

Quickest way to split a delimited String in Java

I am building a Comparator that provides multi-column sort capability on a delimited String. I am currently using the split method from String class as my preferred choice for splitting the raw String ...
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7answers
6k views

Object Oriented Programming Language performance ranking

After reading this post about ideal programming language learning sequence, I am wondering what would have been the answers if the question was performance -instead of learning- oriented ? Since ...
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4answers
1k views

Memory management for fast message passing between threads in C++

Suppose there are two threads, which communicate by asynchronously sending data messages to each other. Each thread has some kind of message queue. My question is very low level: What can be expected ...
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5answers
531 views

How to design a complex REST API considering DB performance?

I've been following some tutorials on how to design REST APIs, but I still have some big questions marks. All these tutorials show resources with relatively simple hierarchies, and I would like to ...
6
votes
1answer
645 views

How to see what parts of your code are run most often?

I would like to be able to see what code in thousands of lines of source code is run most often and takes the longest. The purpose of this would be for optimization. Being able to see what parts of ...
6
votes
3answers
2k views

A question regarding linked list vs vector insert/remove results comparison

I was reading this blog post: http://kjellkod.wordpress.com/2012/02/25/why-you-should-never-ever-ever-use-linked-list-in-your-code-again/ and I found there a code to run: http://ideone.com/62Emz ...
6
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2answers
780 views

Session size management

From what I know, the session information is usually saved on the server. In Java the data is handled as a Map which I guess contains the a String identifier and an object reference which points to a ...
6
votes
6answers
257 views

Should I always store parsed data in database before manipulating?

I am about to start a new project which involves taking an excel file, parsing the data (php-excel-reader) and then using the parsed values in a HTML email. My question is pretty simple. Is it better ...
6
votes
1answer
2k views

Is Collection.stream().filter().forEach() inefficient compared to a standard for each loop?

IntelliJ IDEA recommended to me just now to replace the following for-each loop with a Java 8 "forEach" call: for (Object o : objects) { if (o instanceof SomeObject) { ...
6
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4answers
752 views

Issues to be considered while loading jQuery?

I have seen many answers in SO regarding using Google's CDN to load jQuery instead of loading it from the local server. In essence I understand this is the issue related with decreased latency, ...
6
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1answer
771 views

Is event sourcing ready for prime time? [closed]

Event Sourcing was popularized by LMAX as a means to provide speed, performance scalability, transparent persistence and transparent live mirroring. Before being rebranded as Event Sourcing, this type ...
6
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3answers
2k views

Is the Entity Framework appropriate when all you do is insert records in bulk?

My department develops software to migrate databases for our customers from their old CRM software to ours. In this process we could be inserting up do millions of rows, processed one at a time as we ...
6
votes
1answer
346 views

Does unused code affects the assembly after startup (Memory for example)?

Disclaimer: I come from a PHP background. In PHP, I could have thousands files, which are never loaded, if not needed, due to the autoloader feature (If some code is needed, it would be loaded) How ...
6
votes
4answers
661 views

What are the options when Sql generated by ORM needs tuning?

I am starting working on a web project using django. While researching whether to use Sqlalchemy or raw sql when django orm is not sufficient which is also a question I asked here Raw Sql vs ...
6
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1answer
3k views

How much usage of “likely” and “unlikely” macros is too much?

The often known as likely and unlikely macros help the compiler know whether an if is usually going to be entered or skipped. Using it results in some (rather minor) performance improvements. I ...
6
votes
2answers
2k views

Should I group all of my .js files into one large bundle?

One of the difficulties I'm running into with my current project is that the previous developer spaghetti'd the javascript code in lots of different files. We have modal dialogs that are reused in ...
6
votes
1answer
3k views

Performing client-side OAuth authorized Twitter API calls versus server side, how much of a difference is there in terms of performance?

I'm working on a Twitter application in Ruby on Rails. One of the biggest arguments that I have with other people on the project is the method of calling the Twitter API. Before, everything was done ...
6
votes
2answers
460 views

Versioned Resources to Improve Cacheability

Here's an API concept which could be useful for performance optimisation. It's an example of key-based cache expiry applied to a broader internet-wide context instead of the internal Memcached-style ...
6
votes
1answer
744 views

How can I compute the Big-O notation for a given piece of code? [closed]

So I just took a data structure midterm today and I was asked to determine the run time, in Big O notation, of the following nested loop: for (int i = 0; i < n-1; i++) { for(int j = 0; j < ...
6
votes
1answer
285 views

Optimizing hash lookup & memory performance in Go

As an exercise, I'm implementing HashLife in Go. In brief, HashLife works by memoizing nodes in a quadtree so that once a given node's value in the future has been calculated, it can just be looked ...
6
votes
1answer
700 views

What factors should I be looking at to increase performance in image resizing?

I'm setting up a web app in which people will upload images. Once uploaded the images will be watermarked then resized multiple times (Thumbnails, different sizes etc.) and finally uploaded to Amazon ...
6
votes
1answer
84 views

Strategies for investigating performance of an ASP.NET web application running under .NET 4

I'm trying to compare the performance of an application that has recently been converted from .NET2 to .NET4. From my perfomance tests it seems that although page response times are generally a bit ...
5
votes
10answers
4k views

In term of performance : while , for … Loops VS recursion [closed]

What is better for performance to write the loop as linear e.g. for , while or write it as recursion ?
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2answers
5k views

How to hide the python code from users?

I am developing a paid application in python. I do not want the users to see the source code or decompile it. How can I accomplish this task to hiding the source code from the user but running the ...
5
votes
4answers
580 views

What are the reasons for great performance differences running the same program?

I wrote a Python program that has to perform some expensive spatial searches while holding lots of data in memory. I tried to improve the performance, that is tried different approaches (see my ...
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7answers
9k views

How important is to initialize a variable

How important is it to initialize variables? Does proper initializing avoid memory leaks or have performance advantages?