Concurrency is a property of systems in which several processes are executing at the same time.

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Best-practice to manage concurrency into a basket in a e-commerce website

What is the best practice to manage the case where two customers add in the same time a product whose the stock was only 1 ? Must there be a check in the code of the basket to avoid one of these 2 ...
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4answers
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Functional Programming: right ideas about concurrency and state?

FP proponents have claimed that concurrency is easy because their paradigm avoids mutable state. I don't get it. Imagine we're creating a multiplayer dungeon crawl (a roguelike) using FP where we ...
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10answers
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Concurrency: How do you approach the design and debug the implementation?

I've been developing concurrent systems for several years now, and I have a pretty good grasp on the subject despite my lack of formal training (i.e. no degree). There's a few new languages that have ...
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2answers
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Are all race conditions worth fixing? [closed]

I just wrote the following piece of code (in delphi): procedure Update(Value: Integer); begin // If the last update was yesterday, replace yesterday value if CompareDate(FLastUpdate,Now) <> ...
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10answers
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How to explain why multi-threading is difficult

I am a fairly good programmer, my boss is also a fairly good programmer. Though he seems to underestimate some tasks such as multi-threading and how difficult it can be (I find it very difficult for ...
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UML Diagrams of Multi-Threaded Applications

For single-threaded applications I like to use class diagrams to get an overview of the architecture of that application. This type of diagram, however, hasn’t been very helpful when trying to ...
18
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2answers
717 views

Why does shared state degrade performance?

I've been working under the share-nothing principle of concurrent programming. Essentially, all my worker threads have immutable read-only copies of the same state which is never shared between them (...
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3answers
1k views

What are your thoughts about the Actor Model? [closed]

The Actor Model which is used by Erlang seems to be a very different way to do concurrent programming. What are your thoughts about the Actor Model? Will it be a popular solution for concurrency?
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Why not Green Threads?

Whilst I know questions on this have been covered already (e.g. http://stackoverflow.com/questions/5713142/green-threads-vs-non-green-threads), I don't feel like I've got a satisfactory answer. The ...
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2answers
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SQLite with two python processes accessing it: one reading, one writing

I'm developing a small system with two components: one polls data from an internet resource and translates it into sql data to persist it locally; the second one reads that sql data from the local ...
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1answer
678 views

In what meaningful ways does Erlang prevent race conditions in concurrent programming?

Reading about concurrency in Erlang, reminds me of the Akka concurrency toolkit. Both give you tools to prevent or limit race conditions. But you can send links to mutable data to other processes ...
4
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2answers
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How much configurability to give to users regarding concurrency?

This question is a narrowing-down of these related questions: How much effort should we spend to programming for multiple cores? Concurrency: How do you approach the design and debug the ...
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3answers
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Is there an algorithm to determine the amount of work needed to keep workers busy?

I wrote a multi-threaded program that randomly generates strings, and after generating, checks to see if the string contains a certain value. Namely, StringGenerator and StringChecker. What I'm trying ...
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2answers
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Python threading vs. multiprocessing: Should I learn one before the other?

I'm looking to dive into multithreading or multiprocessing in Python. Question: should I be learning one before the other (for any reason)? If so, which one and why? I've read the pro's and con's in ...
4
votes
1answer
762 views

Is there a formula to figure out the total execution time of sequential asynchronous processes?

I have a set of steps that need to run sequentially over a list of data. However each step only operates on a single piece of data at a time. Because of this, I can run the steps asynchronously. For ...
3
votes
4answers
762 views

Is the synchronized keyword,still used/needed in java?

Is the synchronised keyword still required (ignore backwards compatibility, I'm thinking in terms of writing new code, today) or should we all be using the features available in the Concurrent and ...
3
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1answer
153 views

How do I handle online payment for items with single quantity? [duplicate]

I would like to implement a robust way to handle ecommerce payment for items with limited quantity, like for example exclusive paintings. Payment would ideally be accepted via PayPal and credit cards....
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2answers
221 views

How bad would it be to obtain a lock on every object?

Imagine a hypothetical programming environment that is largely like Java or .NET, i.e. object-oriented, garbage-collected, etc., but with one small change: Every time you call a method on an object, ...