How do I perform a database transaction where I create a new record then make a call to a web service using the new record ID returned from the database which will also manipulate the same database? I could obviously update all tables directly from the same SQLConnection object but the logic within the web service call is subject to chan...
With the following file reading code: using (FileStream fileStream = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.None)) { using (TextReader tr = new StreamReader(fileStream)) { string fileContents = tr.ReadToEnd(); } } And the following file write code: using (TextWriter tw = new StreamWriter(f...
I was wondering if there is a way for a network of N participants to agree that a number from 1 to M was chosen at random. (e.g. not influenced by any of the participants) This has been solved for values of n=2 and m=2 by the coin tossing protocol. Does anyone know of any solutions that can work for arbitrary values of N and M? ...
I've been reading up on this subject for a while. Suddenly the day has come where this solution is a necessity, not just a dream. Through my reading, I've seen the popular differences being (file based, memcached, shared memory (mm), sql table, and custom). The idea we originally thought of was using a ZFS or AFS mounted on each of the...
Other than CouchDB and Native XML Databases (such as eXist), which databases can store and query un- and semi-structured data? I've been handed lots of data in different formats (XML, JSON, YAML, CSV, some custom formats), which I need to merge and work with, but developing a schema in a relational database will be time-consuming and di...
I have a J2ee application where I basically want two objects, created by two separate servlets to communicate directly and I need these intances to be stable, i.e. to "know" each other during the session. The sequence is roughly: Client sends a request to Servlet #1, which creates object A Client sends a second request (after the fir...
I'm trying to get my head around AMQP. It looks great for inter-machine (cluster, LAN, WAN) communication between applications but I'm not sure if it is suitable (in architectural, and current implementation terms) for use as a software bus within one machine. Would it be worth pulling out a current high performance message passing fram...
Hi all, We use Incredibuild here to compile our code in a distributed fashion. I was wondering if there are any open source (or free) alternatives to use on a home network? Failing that, are there any other simple solutions with good integration with Visual Studio out there? EDIT: I should say that I am quite happy to get my hands d...
How does one design loosely-coupled systems which may often require data from each-other but don't necessarily belong in the same category? For instance, lets take the old Pet-shop example one-step further and create a pet-store franchise. Each pet-store has its own website listing their contact information, promotions, and current stoc...
Hi, I'm in need of a distributed file system that must scale to very large sizes (about 100TB realistic max). Filesizes are mostly in the 10-1500KB range, though some files may peak at about 250MB. I very much like the thought of systems like GFS with built-in redundancy for backup which would - statistically - render file loss a thing...
Ignoring payload size, what is relative difference in latency between an in-proc call (say in C++ or Java), a socket call to a process on the same machine, and a socket call to a process on another machine? This can be expressed as a minimum latency in ns/ms or in terms of relative orders of magnitude. I'm looking for something similar...
I've been evaluating ActiveMQ as a candidate message broker. I've written some test code to try and get an understanding of ActiveMQ's performance limitations. I can produce a failure state in the broker by sending messages as fast as possible like this: try { while(true) { byte[] payload = new byte[(int) (Math.random() *...
In short: Is there any known protocol for remote process management? I have a system that contains several applications, each has it's own computer in a local network. When the applications are up and running, they communicate without any problems. What I'm interested in is a protocol to manage the remote applications startup, shutdown...
Does anyone know a simple load balance algorithm (formula) that relates users connected, cpu load, network load and memory usage? This will be used to compare various servers and assign to a new user the best at the moment. Thank You. ...
I have a team of developers distributed Globally over different time zones. what are the best tools to achieve maximum productivity in such a team? I am looking for: Source Control Bug Tracking Build Management Any other thing that may help Thanks ...
I recently discovered Erlang and am now working my way through a couple of tutorials. By now I'm looking forward to actually implement something as a hobby project. I'm not really interested in yet another chat server. I would like to code something more interesting (yes I'm aware that this is a rather fuzzy term) which is also manageabl...
Currently, I only know a way of doing RPC for POJOs in Java, and is with the very complex EJB/JBoss solution. Is there any better way of providing a similar functionality with a thiner layer (within or without a Java EE container), using RMI or something that can serialize and send full blown objects over the wire? I'm not currently i...
Are there any good language-agnostic distributed make systems for linux that are secure and free? Background Information: I run scientific experiments (computer-science ones) that sometimes have large dependency trees, occasionally on the order of thousands or tens of thousands of tree nodes. This dependency tree is over the data file...
I'm interested in cross-colo fail-over strategies for web applications, such that if the main site fails users seamlessly land at the fail-over site in another colo. The application side of things looks to be mostly figured out with a master-slave database setup between the colos and services designed to recover and be able to pick up m...
Is there a utility/library that facilitates the coordination of tasks between multiple servers? For me, I need to run scheduled tasks, copy lots of data between servers, and restart processes (a series of dependent operations that occur on different machines in a cluster). I can go with cronjobs and batch scripts, although I can't he...