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

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5answers
505 views

How to ascertain from the users if performance tuning has had the desired effect [closed]

So you've made some code changes that should hopefully speed up some part of an application. But there is just one problem - you don't know how it will perform in live. Different networks, different ...
0
votes
1answer
146 views

Finite Element Shader

I am working on a geometric wrapper for a space jet exhaust impingement solver. A key part of the solution is determining what the jet can "see" and therefore hit. My model is grouped with nodes or ...
170
votes
13answers
49k views

Should we avoid object creation in Java?

I was told by a colleague that in Java object creation is the most expensive operation you could perform. So I can only conclude to create as few objects as possible. This seems somewhat to defeat ...
1
vote
4answers
99 views

is stored procedure having multiple UNION efficient than running all SQL's in parallel?

I have below in my stored proc if then SELECT TABLE1.COLUMN1,TABLE1.COLUMN2,TABLE1.COLUMN3,TABLE1.COLUMN4 FROM TABLE1,TABLE2 where criteria1 (covers functionality 1) UNION SELECT ...
4
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0answers
54 views

Estimate if benchmark sampling difference is significative

In order to estimate the fastest function in various cases in a non fully deterministic context, I'm running an experiment calling one or the other at random and recording the duration of the ...
0
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2answers
78 views

JSON or XML or other - most time efficient for largely “read” of structured data

Considering that using a relational DB or other hierarchical or such databases is not an option, looking for the alternative approach using a simple (but very fast, efficient, distributed KV-store). ...
25
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11answers
2k views

How to deal with misconceptions about “premature optimization is the root of all evil”?

I've encountered many people who are dogmatically against anything which can be considered "optimization" in the general English-language sense of the word, and they very often quote verbatim the ...
-1
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2answers
90 views

Does sql use hastables for indexes? [closed]

Are there other ways of indexing?, Which are the more used? Does sql have an standard for indexes, it uses hash tables?
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0answers
21 views

Reading a file in Python: slurp or filter? [migrated]

I want to compare the effect of processing a stream as a filter (that is, get a bit, process, rinse), against slurping (that is, get all information, then process). However, when I run the two codes ...
0
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0answers
17 views

Finding performance (network perspective) differences between mobile websites and their corresponding applications?

I'm researching performance differences when using an application, compared to its mobile website counterpart. To my help I looked into what other people define as performance(since it's a broad term) ...
2
votes
0answers
68 views

Maximising data processing speed: in-memory or write to db first?

Currently working on a system which allows users to upload data files, which we then "clean" (i.e. process in various ways). Speed of processing and return to the user is an important consideration, ...
1
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1answer
78 views

Clairvoyance in caching - optimal strategies?

This question relates to the question here, but I'll generalise it so that you can answer effectively without reading all of that. Context: Imagine you had a large set of data greater than your ...
2
votes
1answer
65 views

Caching in '3D' - data-structures and octree recursion - hrrm!

The Situation: I have 68GB of data that is conceptually realized as a 3D matrix of 8-bit values with dimension 4096*4096*4096. I need to access multiple sections of this data for processing in a ...
2
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3answers
246 views

Design periodic batch notification system

Problem: I am trying to design a system which takes requests from customers in real time and log them in a database. For example - request to purchase an item. The customer then gets a unique ...
25
votes
11answers
2k views

Does Refactoring towards Looser Coupling, Smaller Functions, and Separate Classes affect System Performance? (and Should I Care)

Lest you be confused by what's to follow, here is the driving idea behind the question: I always intended the question to be what it is. I may not have articulated it well originally. But intent ...
21
votes
5answers
13k views

JIT compiler for C, C++, and the likes

Is there any just-in-time compiler out there for compiled languages, such as C and C++? (The first names that come to mind are Clang and LLVM! But I don't think they currently support it.) ...
14
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6answers
643 views

Do changes in performance violate the Liskov Substitution Principle?

Say I have: interface Thing { GetThing(); } class FastThing : Thing { public int GetThing() { return 1; } } class SlowThing : Thing { public int GetThing() { ...
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 ...
1
vote
1answer
58 views

«Heavy» object initialization: within each thread or outside and then pass it to the threads as parameter?

Let say there is an array of strings, I have to process. I'm using a «heavy» third-part object which gets the string and performs its analysis. In order to optimize a performance, I create a number of ...
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votes
1answer
164 views

Java: Why's this For-Loop thousands of times slower?

So I have a simple method I'm calling millions of times a second, and I noticed that it was taking 16% of all processing time!! The offensive routine is as follows: public void placeHolder(){ ...
3
votes
3answers
254 views

Iteratively improve software architecture & quality in an agile process?

Or to put it another way how to ensure that architecture or quality doesn't suffer, doing agile. Some of the understandings in handling architecture in agile are below(generally applies to testing as ...
4
votes
1answer
73 views

How do you handle Performance tasks in Agile?

How is the Agile process affected if a stakeholder requests that a specific operation in the software need to perform better? This could mean that it runs very slow for a customer's needs (even with ...
0
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1answer
59 views

Does variable type specification lead to any performance difference?

Let's say I have a very long method which basically creates a responsive and resizable layout for a user interface by using a few fixed values and a few variable ones taken from an element's ...
1
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0answers
67 views

Guaranteed message sending for messages of different priority for different modules

We have created a message que system using priority messages. The idea behind this is as follows: We have a list of clients. All clients know if (and what kind of priority) messages they have ...
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4answers
162 views

Nested For Loops JavaScript

I have an app which gets data from the database (MongoDB) in JSON format. The returned data contains nested arrays and I want to access the values in the nested arrays. The returned JSON format looks ...
8
votes
2answers
162 views

Why does expressing calculations as matrix multiplications make them faster?

In Google's MNist tutorial using TensorFlow, a calculation is exhibited in which one step is equivalent to multiplying a matrix by a vector. Google first shows a picture in which each numeric ...
0
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1answer
262 views

How could this be considered performant code?

I came across this (Java) code yesterday and can't figure out why someone would have done this in any language. In what scenario, language, paranoid delusion would "removing" values from an ...
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 ...
1
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4answers
316 views

What is the ninja performance gap, why is it so large, and how can we overcome it?

According to this abstract: The "Ninja gap" [...] is the performance gap between naively written C/C++ code that is parallelism unaware (often serial) and best-optimized code on modern ...
3
votes
1answer
311 views

Bad c++ code design? [closed]

This is bothering me a long time. I feel like I am doing mistakes on the code design relative to the performance. I never had any teacher to indicate my mistakes so its hard to me to make it right in ...
6
votes
4answers
2k views

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 ...
1
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0answers
21 views

Distributed Design to Speed Up Video Processing

Currently I have one web server running Django, which takes a series of images from a user, uploads them to an Amazon S3 bucket, and finally calls an Amazon Lambda instance, which runs a python script ...
1
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0answers
36 views

Best way to handle multiple proxies and HTTP requests

I need to develop a solution for a problem that requires multiple HTTP/ Socks proxies for different HTTP requests. The solution needs to be cross platform. Here is my idea how it needs to work: ...
1
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2answers
95 views

Load to list in one loop and then process list in another or do it all at once

I have a dataset full of rows that I must initialize into myclass and then process. I am currently looping through each row in the dataset, initializing a new instance of myclass, then adding that ...
2
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3answers
135 views

Is denormalising a data structure essentially a code optimisation, to which the normal rules apply?

One of Bloch's Effective Java items 55: Optimize judiciously extends Jackson's rules on optimization: Rule no. 1: Don't optimise! Rule no. 2 (for experts): Don't optimise yet! Extra ...
0
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1answer
131 views

Huge long addition overhead compared to Native call?

A run a simple test JDK 1.7.0_45 (Windows 7, 64bit): Test 1: long start = System.nanoTime(); for (int i=0; i < 1000000; i++) { System.currentTimeMillis(); } elapsed = System.nanoTime() - ...
0
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0answers
77 views

Options for implementing database and programming logic for statistics application?

I am implementing a statistics driven web application. The statistics relate to sporting events. Right now I have a postgresql database with a table that holds a row for each match. This is a ...
4
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0answers
72 views

Using mysql 5.7 Json Columns for EAV

I am developing an e-commerce product and I have been able to implement all functionality and am left with allowing users to create additional attributes for a product. Right Now I have two options. ...
0
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0answers
102 views

Advice on program performance after changes

So, the situation is like this: For the past two years, I have implemented a class in c# which is used to filter different fields from different tables in database (SQL), for reporting purposes. Now ...
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 ...
100
votes
11answers
33k views

What backs up the claim that C++ can be faster than a JVM or CLR with JIT? [closed]

A reoccurring theme on SE I've noticed in many questions is the ongoing argument that C++ is faster and/or more efficient than higher level languages like Java. The counter-argument is that modern JVM ...
6
votes
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 ...
38
votes
19answers
4k views

Would you purchase hardware with your own money to use at work to do your job better? [closed]

At work, I was given a reasonably-spec'ed machine (dual quad 2GHz, 4GB RAM, 160GB 7200RPM drive, Win7), but it was lacking in a few places (HDD / RAM). The IT staff was OK with me replacing hardware ...
2
votes
1answer
111 views

Improving sampling algorithm

I am having a bit of trouble designing a new feature at the moment. It is part of a resource management system. I was wondering if anyone has experience doing anything similar. I'll try to explain: ...
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 ...
1
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0answers
32 views

How can I test for performance issues in a specific piece of code? [duplicate]

I've inherited a problem from a programmer that isn't with our group anymore - a piece of our application suffers from performance issues under a particular set of circumstances. I can replicate ...
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 ...
3
votes
1answer
121 views

How are objects treated in an anonymous inner class?

Lets take this for example... entryText.addTextChangedListener(new TextWatcher() { TextView wordCount = (TextView) findViewById(R.id.wordCount); TextView charCount = (TextView) ...
11
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5answers
6k views

Java Heap Allocation Faster than C++

I already posted this question on SO and it did ok. It was unfortunately closed though(only needs one vote to reopen) but someone suggested I post it on here as it is a better fit so the following is ...
14
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3answers
1k views

What makes a large and complex software product slow? [closed]

For a reason that is largely irrelevant, I installed Delphi 7 once again in such a long time. I have to say, I was completely blown away - in a way I haven't been for rather a while. This is not how I ...