Re: [Proxool-developer] concurrency bug in Prototyper class?

[Bill H. <bi...@lo...>]

Is that a problem that corrects itself? In other words, is it a temporary
problem where a connection is refused when it didn't have to be but that the
connection count does end up being correct? - Bill

2009/6/19 Matt Salafia <msa...@gm...>

> It seems Class Prototyper should either acquire the lock on private member
> 'lock' whenever it reads or modifies 'connectionCount' or make
> 'connectionCount' a volatile variable.
>
> Prototyper.buildConnection( ) acquires the lock to read and modify
> 'connectionCount' but other methods do not: Prototyper.sweep( ),
> Prototyper.connectionRemoved( ) and Prototyper.getConnectionCount().
>
> I started poking around after my application started seeing
> ProxoolExceptions indicating the maximum connection count had been reached
> and discovered what appears to be a memory visibility issue.  If calls to
> Prototyper.connectionRemoved( ) and Prototyper.buildConnection( ) happen in
> different threads there could be unwarranted ProxoolExceptions for reaching
> the maximum connection count - a 'connectionPool' decrement might not be
> visible to the threads calling Prototyper.buildConnection( ).
>
>
>
>
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