Locking allows different types of resources to be locked by a transaction.

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1answer
41 views

Recursive spinlock for C using ASM, revision #1

Precursor for this revision here in code-review: Recursive spinlock for C using ASM Improvements have been made thanks to forsvarir. Now I am trying to optimize this lock so it becomes more ...
4
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3answers
118 views

Exclusive access to objects

Take a look at following code: ...
2
votes
1answer
52 views

Function to lock a file using memcache, version 2

Based on suggested reviews for Function to lock a file using memcache, I have modified the code to ...
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1answer
48 views

Function to lock a file using memcache

I have a web application where I list files in the UI to many users at the same time. There are many people who monitor the files and process them. However, I don't want multiple users processing the ...
3
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1answer
63 views

Simulating memcache get and set race condition and solving it with add

Memcache get and set can hit a race condition if you use them together to achieve something like locking because it is not ...
3
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1answer
84 views

Python program to lock and unlock files

The code takes srcPaths and actionType as parameters. The former is a string with tab-delimited file paths, while the latter is ...
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0answers
34 views

AutoCloseable Lock

Surprisingly, this question has no satisfactory answer. A safe usage of a LockCloseable would be like ...
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1answer
59 views

Recursive spinlock for C using ASM

My history of C/ASM locks here in codereview: Simple spinlock for C using ASM Simple spinlock for C using ASM, revision #1 (basis for this approach. If this one fails, then so will the one below.) ...
3
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1answer
50 views

Simple spinlock for C using ASM, revision #1

Revision #1 for Simple spinlock for C using ASM The code: ...
5
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1answer
64 views

Simple spinlock for C using ASM

This is my second attempt to make simple lock using extended assembly. See http://stackoverflow.com/questions/37241553/locks-around-memory-manipulation-via-inline-assembly/37246263 The code: ...
2
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1answer
36 views

Thread-safe Bloom Filter in Java

I have tried to implement a Bloom Filter in Java here. https://github.com/srirammanoj/skynet/tree/master/bloomfilter I just wanted to know if my implementation can be called 'thread-safe' , and if ...
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0answers
25 views

Exclusive row lock

I'm in a situation where I need to manage a kind of FIFO process within a SQL procedure. The procedure is called by a multithreaded windows application. I've created a table which look like this: <...
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0answers
8 views

Robustly send notifications from multiple processes

We have Notifications stored in a notifications table, which is worked on by multiple background workers. The notifications table has these relevant attributes: id (primary key, unique) send_at (...
3
votes
1answer
80 views

Queuing web service calls

Every call to the web service goes through a custom queuing system. This has a limit that is set to 1. Every call that enters the same time with another call is purged and not handled. Not sure if ...
0
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1answer
43 views

Unlocking spreadsheet files quickly - follow-up

I recently posted a program I made to unlock spreadsheet files( see also ), I've taken all of your advice and made it more Ruby like, it has no shell commands in it, and uses ...
4
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1answer
62 views

Unlocking spreadsheet files quickly

I've created a program for my job that unlocks spreadsheet files quickly and efficiently. What we use to have to do before this program is we'd have to go into the system, search for the file, kill ...
4
votes
2answers
156 views

Parallel foreach with configurable level of concurrency

The purpose of this code is to let me loop over 100 items (up to MAX_CONCURRENT at a time), performing some action on them, and then return only once all items have ...
2
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1answer
63 views

New caching and deferred evaluation strategy

This is a simple wrapper class for a lambda expression, that stores one as Expression and hands it back out either as Expression,...
5
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1answer
62 views

Lock implementation using atomics

I was recently given an interview and was asked to write my own lock implementation using atomics, but not necessary reentrant. I didn't answer the question, but at home, I wrote this code. Please ...
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2answers
1k views

Locking mechanism in C#

I would like you to review the locking mechanism I implement in C# class. Will it be working correctly with many threads? Please don't mind rest of the code because I just try to repair the class ...
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2answers
117 views

Item-level locks for a large number of items

Background I'm working on a system that records information about a large number of external documents. These documents are organized by "repository". There can be a modest number of repositories (...
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0answers
130 views

Simple distributed lock manager server based on zmq

I wrote a simple server to distribute locks on a network. It is used in a multi-server environment with a shared home directory to secure non-multiprocessing safe file writing (...
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1answer
44 views

ReadWriteMap implementation

I had a task to realize ReadWriteMap ...
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2answers
628 views

Simple Implementation of a ReentrantLock

An implementation of a ReentrantLock: ...
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1answer
71 views

Thread-safe removewhere

I'm trying to implement a HashSet that it's accessed from different thread for querying, adding or deleting elements. It doesn't make sense to use a Dictionary for I got several search keys so I won't ...
3
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1answer
151 views

Simple read/write lock without using a critical section

I have implemented a simple read/write lock without using a critical section. I have tested my code by running 50 threads reading and writing the same data. .h file ...
7
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2answers
692 views

Spinlock for C++ kernel (with x86 ASM)

This is some prototype code for a spin-lock for my toy operating system. Bear in mind this means there are no standard library routines to fall back on. It's also for C++11 compilation and will only ...
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2answers
232 views

Generic object pool class using Spinlock/Monitor

I've written the following object pool class, and because this is my first encounter with synchronization primitives, I need reinsurance from an expert that this code is safe. I've tested it myself ...
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1answer
2k views

Async distributed locking with StackExchange.Redis [closed]

I have been trying to write an analogy to this approach to distributed locking with two differences: making it asynchronous making it work with StackExchange.Redis rather than AppFabric Cache. My ...
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1answer
46 views

Simple file locking wrapper command in C

A simple command that wraps another command, locking a file first. It is similar to flock, just simpler. ...
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3answers
594 views

Using goto to wait on the result of a database query to change

This is a small personal project where most non-sensitive data is distributed to some globally hosted CDN servers, which store the JSON. Now one problem we've seen during testing is a few deadlocks ...
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1answer
178 views

Deadlock watchdog in a server to defend against poorly written extensions

In the Red5 server we have no control over what implementers do with their applications. As such, we have attempted to implement code that would prevent them from causing bad things to happen. This ...
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2answers
336 views

Generic Object Pool in C#

I have a limit of 100 sessions (each session held in an object). Many threads will be requesting sessions, and it is very possible that all 100 sessions could be in use at any time. I'm a Junior ...
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6answers
973 views

Reading a line of text from a socket

I tend to write code, with very few comments, and few line breaks. I'm currently just a student at a University. I've had professors tell me one way or another to comment, but I have a hard time with ...
7
votes
1answer
359 views

Simple, encapsulated C++ logger that can deal with fork/exec situations

Motivation: for whatever reason, some of the available 3rd party logging libraries don't really deal with programs that get fork'ed/exectuted well. For instance, ...
3
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2answers
141 views

Locking a remote file

I am using Java to modify remote files in different machines by ssh. At the same time, only one thread is allowed to modify the file in one machine. I implement the logic like this: ...
4
votes
1answer
2k views

Monitoring progress in Parallel.ForEach every minute

I'm using Parallel.ForEach to download 500K URLs and I want to monitor the number of URLs that have been successfully downloaded each minute. ...
10
votes
2answers
308 views

RAII pattern for downgradable ReadWriteLock

The example for downgrading ReentrantReadWriteLock in the Java documentation seems really unsafe when handling exceptions. I tried to write a simple class to ...
5
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1answer
140 views

Is my spin-lock implementation correct?

I'm working on a project where a spinlock is more appropriate than a mutex, and after few tries I came up with: ...
3
votes
1answer
39 views

Good approach to raise an exception

I have class House and module Lockable. Locking and unlocking House should reflect the real ...
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2answers
122 views

SynchronizedArrayList implemented using reader writer synchronization

I am trying to understand the workings of reader writer locks. For the sake of learning, I implemented reader writer synchronization by my own. I implemented ...
7
votes
1answer
1k views

Portable C++ boost::interprocess::mutex

I was looking for long time around to have a portable robust solution for multiprocessing synchronization. Who touche this things know that good solution are boost::iterprocess named sync objects. ...
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0answers
245 views

Lock a process in PHP

We had a situation where it was necessary that a script only be running in one process at a time. The solution was to make a "LockByProcess" class that checks a database for an existing process, and ...
3
votes
1answer
384 views

Mutualising multi-threaded calls to EJB from Servlet

I have a Servlet that makes an EJB call to a backing server which takes about a second to return some data that changes reasonably regularly. I can't cache the data on the servlet-side, so I have ...
7
votes
2answers
2k views

A simple semaphore in Java

It is a simple semaphore in Java. Although it passes all their tests with flying colors, I'm still not sure it's correct. For example, the last thing I wasn't sure about was ...
3
votes
2answers
771 views

Prevent re-entrant function call in C++

The purpose of this is to prevent a re-entrant function call in a single thread, e.g. prevent the situation where func() calls ...
3
votes
1answer
133 views

Moonshot & `Thread.Abort` - dealing with the fallout

Recently, I encountered an anomaly in the manner by which a worker thread was terminated. It prompted me to do some searching and I realized that I was constructing thread code in a haphazard manner. ...
2
votes
1answer
206 views

Social sharing counter plugin [closed]

I am creating a social sharing counter plugin for my WordPress blog. I want to fetch the counts of number of likes, shares, Facebook comments (I am using Facebook comment box), twitter tweet counts ...
2
votes
1answer
237 views

Testing Promises vs Lock performance

I'm not sure if my lock usage is correct and safe. I wanted to know what will be best approach to deal with situation when one thread have to wait for being initialized by another so I written this ...
5
votes
1answer
225 views

Using CountDownLatch for blocking the reads if writes are happening

I am trying to implement lock by which I want to avoid reads from happening whenever I am doing a write on my three maps. Requirements: Reads block until all three maps have been set for the first ...