[Libpqxx-general] Connection Pool

[Jeroen T. Vermeulen]

On Tue, July 14, 2009 01:01, Manuel Argüelles wrote:

> I'm looking forward to build a connection pool class, do you know if
> there's
> any example code or similar that may help me?, if possible I'll like it to
> be
> multi thread-safe.

Nice!  There's an example that might be of use on Launchpad:

https://code.launchpad.net/~jtv/libpqxx/connection-pool

That's just a sketch though—no testing, and I don't think I got the BOOST
thread synchronization right.  It's also a bit experimental in that it
uses the shared_ptr destructor to hand back a connection to the pool when
the thread that held it destroys its last reference to the connection.


> So far what I have thought  is to create n lazy connection objects, the
> problem comes in how to know which connection is free (to assign the
> transaction to) and dealing with connection errors.

You could keep track of that separately.


> Or do you think it will be enough to have an static counter of the
> connections
> and just assign the transactions to the next one (as in a loop)?

No, because you still won't know whether the last thread that held a
connection is done with it!


Jeroen