I have recently completed some study of erlang, and was intrigued by scala for its feature set and the ease of interpolating with java (and possibly .net) applications. I am finally studying actors and was wondering if there is an actor mechanism that currently works in .net. I have looked at the libararies that come down with sbaz an...
This question certainly applies to a much broader scope, but here it is. I have a basic ecommerce app, where users can, naturally enough, place orders. Said orders need to have a unique number, which I'm trying to generate right now. Each order is Vendor-specific. Basically, I have an OrderNumberInfo (VendorID, OrderNumber) table. Now ...
The question pretty much says it all. Does anyone know of any way to get the collection classes from the System.Collections.Concurrent namespace in .NET 3.5? I guess what I'm asking is whether anyone has gone through the trouble of porting these classes to their own DLL that could be accessed from .NET 3.5. ...
I need to run in parallel multiple threads to perform some tests. My 'test engine' will have n tests to perform, each one doing k sub-tests. Each test result is stored for a later usage. So I have n*k processes that can be ran concurrently. I'm trying to figure how to use the java concurrent tools efficiently. Right now I have an exe...
I am using the parallel data structures in my .NET 4 application and I have a ConcurrentQueue that gets added to while I am processing through it. I want to do something like: personqueue.AsParallel().WithDegreeOfParallelism(20).ForAll(i => ... ); as I make database calls to save the data, so I am limiting the number of concurrent thr...
Word up y'all I recently successfully experimented with Scala futures, got future { my shiznit } all over da place. I'm pleased as punch w/ the gains I'm seeing from the parallelism and whatnot, but I'm only seeing 4 worker threads. Wanna see some more. I've been looking all over for how I can crank up the number of threads to 11, but n...
I'm looking at output of SP_WhoIsActive on SQL Server 2005, and it's telling me one session is blocking another - fine. However they both are running a SELECT. How does one SELECT block another? Shouldn't they both be acquiring shared locks (which are compatible with one another)? Some more details: Neither session has an open transa...
I'm writing a tiny script that calls the "PNGOUT" util on a few hundred PNG files. I simply did this: find $BASEDIR -iname "*png" -exec pngout {} \; And then I looked at my CPU monitor and noticed only one of the core was used, which is quite sad. In this day and age of dual, quad, octo and hexa (?) cores desktop, how do I simply pa...
I want to define a trigger in PostgreSQL to check that the inserted row, on a generic table, has the the property: "no other row exists with the same key in the same valid time" (the keys are sequenced keys). In fact, I has already implemented it. But since the trigger has to scan the entire table, now i'm wondering: is there a need for...
Hi, I want to have a record editor in PHP and I want to be able to detect if it's been updated already during the commit. I've already read some solutions, and they suggest a timestamp column, or rowversion. Does anyone have any other general solutions that do not involve modifying the database structure? I was going to hash the reco...
I really like these tools when it comes to the concurrency level it can handle. Erlang looks like much more stable solution but requires much more learning and a lot of diving into functional language paradigm. And it looks like Erlang makes it much better when it comes to multi cores CPUs(fix me if I'm wrong). But which should I choos...
I have heard that in Haskell, creating a multi-threaded application is as easy as taking a standard Haskell application and compiling it with the -threaded flag. Other cases, however, have described the use of a par command within the actual source code. What is the state of Haskell multi-threading? How easy is it to introduce into prog...
When it comes to virtualization, I have been deliberating on the relationship between the physical cores and the virtual cores, especially in how it effects applications employing parallelism. For example, in a VM scenario, if there are less physical cores than there are virtual cores, if that's possible, what's the effect or limits pla...
I have a server that has several clients C1...Cn to each of which there is a TCP connection established. There are less than 10,000 clients. The message protocol is request/response based, where the server sends a request to a client and then the client sends a response. The server has several threads, T1...Tm, and each of these may se...
Lets say UserA and UserB both have an application open and are working with the same type of data. UserA inserts a record into the table with value 10 (PrimaryKey='A'), UserB does not currently see the value UserA entered and attempts to insert a new value of 20 (PrimaryKey='A'). What I wanted in this situation was a DBConcurrencyExcep...
Hi there, This might be a stupid questions but I wanted to know what happens if two users edit some data at once and then both click submit at the same time, I assumed Rails handled requests one after the other and so someone would get an error message but is this correct? Thanks Once one person has edited data I dont want it to be ac...
I'm looking for Java libraries/applications which are parallel and feature objects that can be queried in parallel. That is, there is/are objects in which multiple types of operations can be made from different threads and these will be synchronized. It would be helpful if someone could ideas of where I could find such applications as w...
Is it possible to launch two kernels that do independent tasks, simultaneously. For example if I have this Cuda code // host and device initialization ....... ....... // launch kernel1 myMethod1 <<<.... >>> (params); // launch kernel2 myMethod2 <<<.....>>> (params); Assuming that these kernels are independent, is there a facility to...
Good afternoon, Somebody asked me a question today and neither did I know the answer nor could I find it in the documentation. This person simply asked me if the sapply function in R was making concurrent calls to the function you want to apply to the list, or if the computation is done sequantially. Does anybody know the answer? Wha...
Hi, I got a C++ program (source) that is said to work in parallel. However, if I compile it (I am using Ubuntu 10.04 and g++ 4.4.3) with g++ and run it, one of my two CPU cores gets full load while the other is doing "nothing". So I spoke to the one who gave me the program. I was told that I had to set specific flags for g++ in order t...