Well blocking IO means that a given thread cannot do anything more until the IO is fully received (in the case of sockets this wait could be a long time). Non-blocking IO means an IO request is queued straight away and the function returns. The actual IO is then processed at some later point by … Read more
First of all, non-blocking I/O has nothing in common with green threads or coroutines, but it can affect how they’re scheduled. Now: Twisted is a classic non-blocking I/O framework — application code is written in async style using callbacks. Gevent and eventlet use the greenlet library for coroutines/greenthreads/greenlets. There is one dedicated greenlet for running … Read more
You can use SQLA in a non-blocking style using gevent. Here’s an example using psycopg2, using psycopg2’s coroutine support: https://bitbucket.org/zzzeek/green_sqla/ I’ve also heard folks use the same idea with pymysql. As pymysql is in pure Python and uses the sockets library, gevent patches the socket library to be asynchronous.
If a program is lock-free, it basically means that at least one of its threads is guaranteed to make progress over an arbitrary period of time. If a program deadlocks, none of its threads (and therefore the program as a whole) cannot make progress – we can say it’s not lock-free. Since lock-free programs are … Read more
The code you mention is IMO poorly coded and commented. That code does not conform to POSIX practices for portability as described in Setting Terminal Modes Properly and Serial Programming Guide for POSIX Operating Systems. That code does not mention that it uses non-canonical (aka raw) mode, and reuses the “blocking” and “nonblocking” terminology to … Read more
Currently there are 2 basic concepts to handle parallel access to a web-server with various advantages and disadvantages: Blocking Non-Blocking Blocking Web-Servers The first concept of blocking, multi-threaded server has a finite set amount of threads in a pool. Every request will get assigned to specific thread and this thread will be assigned until the … Read more
You need to use multi threading to perform this task in which one thread (the main thread) will do the processing and the other thread will be used to show the messagebox.
With the async approach you get to send the data to the client when its ready, instead of blocking a thread the whole time its being prepared. For http-kit, you should be using an async handler described in the documentation. After delegating the request to an async handler in a proper way, you can implement … Read more
Before discussing which one is better, let’s take a look at the difference between these commands. Both DEL and UNLINK free the key part in blocking mode. And the difference is the way they free the value part. DEL always frees the value part in blocking mode. However, if the value is too large, e.g. … Read more
Richard Dutton has a solution on his blog: while (true) { if (Console.KeyAvailable) { ConsoleKeyInfo key = Console.ReadKey(true); switch (key.Key) { case ConsoleKey.F1: Console.WriteLine(“You pressed F1!”); break; default: break; } } // Do something more useful }