Re: Connection pool issues with clsql

On Tue, 2010-02-02 at 17:12 -0500, Nathan Bird wrote:

> 
> >From what I recall looking at, connection pooling still has some
> potential for race conditions from here:
> http://lists.b9.com/pipermail/clsql/2009-June/001717.html.

That one got fixed - see the change log entry:

 02 Jun 2009  Kevin Rosenberg <kevin-HJRc7zDS/[email protected]>
        * Version 4.0.5
        * sql/database.lisp: Add process-lock for deleting database from
        a pool (thanks to Ralf Mattes).


But we still have some "issues" with connection pooling. One nagging
problem we repeatedly run into: the pool never realeases connections, so
if you have a peek of parallel connections the pool keeps them hanging
around.

 HTH Ralf Mattes
 
> Also if you are using view-class objects, each object stores its
> connection and uses that one, so if you return a connection to the pool
> it can still be referenced and used by an object even as another object
> is trying to use that same connection in a different thread. I.e. don't
> let objects outlive a connection to the database.
> 
> Also there are a couple of patches here:
> http://github.com/UnwashedMeme/clsql/commits/uncontroversial/sql/pool.lisp
> that have not yet been merged into master (they're on the list) attempt
> to verify that a connection gotten from the database is still in working
> order--normally another query to the database to ensure validity. This
> still tends to be faster than building a new connection altogether.
> 
>