Shared db pool

[Alex Khmara]

My task involves many worker threads, each of them uses Curl instance to 
do one or several requests and one Mysql connection instance to store 
data and do some aggregations. ALso sometimes these threads do other work 
that don't require these resources.

So I want to make two pools (one for Curl and one for Mysql connections), 
so that number of DB connections (or Curl instances) will be lower than 
number of threads, so I cannot just use DataPool.WorkerLocalStorageRange.

So I'm trying to create shared pool. And there arises question:

if I have this code:


class SharedPool {

...
	Mysql* get() {
...
		return cast(Mysql*) connections[freeIndex];
	}
...
	Mysql*[] connections;
}

shared SharedPool pool;


when I will get syncronization overhead: only on access to SharedPool or 
on every access to Mysql instance?

What I really want - is to NOT have any shared-related code after getting 
some Mysql instance and before returning it to pool, so Mysql instances 
must be essentially non-shared. Is it possible?