I've been looking at your std.parallelism module and am really interested in it,
but there is one problem that I have run into that I can't seem to find a
solution. If I have code that requires a database connection in each thread, I
don't really want to be creating and then deleting a lot (e.g. 500,000) of
connections while using taskPool.parallel. Normally I would create a set of
objects that extend Thread and create a single connection in each. Can you offer
a suggestion how I might handle this situation? Here is an example of my problem:
string[] array = ...;
foreach (string element, taskPool.parallel(array))
{
//Create database connection
//Run some complex code with database query
}
I did come up with a solution, but it was a bit of a hack. I changed the
definition of TaskPool to be a templated class:
final class TaskPool(ThreadType : Thread = Thread)
And this allowed me to create instances of my own worker class. The final usage
looks like the following:
//Init the thread pool
TaskPool!(Worker) pool = new TaskPool!(Worker)(THREADS);
Worker mainThreadWorker = new Worker();
try {
foreach (string element; pool.parallel(list, 4))
{
if (thread_isMainThread())
mainThreadWorker.work(element);
else
(cast(Worker)Thread.getThis()).work(element);
}
} finally {
pool.finish();
thread_joinAll();
}
class Worker : Thread
{
private MysqlConnection db;
public this(void delegate() dg)
{
super(dg);
db = new MysqlConnection();
}
}
The code works and I am using it to do millions of calculations. Thoughts?
Thank you,
Jonathan
