Multithreading design

Posted on 16th Feb 2014 by admin

Hi

I have come up with a Singleton class that manages a pool of database connections. Basically the pool is a queue in which I have stored some connection objects. When ever a client calls any of the database class methods a connection object is popped from the queue and when done the connection is pushed on the queue. If the there are no more connections then that thread has to wait for signal when the pool has a connection then a signal is broadcasted to the wait thread. And now some code

Code: if(dbPool.size() != 0)
{
pthread_mutex_lock(&criticalSection);
DNativeDb activeDbObj = dbPool.pop();
pthread_mutex_lock(&criticalSection);
...
}First Question: Is it ok to put pop() under the a mutex_lock

elsewhere in code

Code: pthread_mutex_lock(&criticalSection);
dbPool.push(activeObj);
if(dbPool.size() == 1)
{
pthread_cond_broadcast(&cond);
}
thread_mutex_lock(&criticalSection);Second: When my pool has 1 connection object left then I need to broadcast incase some thread that might be waiting can then acquire the object. Is this the right way to achieve pool based connecting handling. Please guide and suggest if I am going wrong anywhere.

Thanks

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