Re: [PDO] Shared behavior of persistent connections

Hi Matteo! Thanks for responding. :-) I'm forwarding to internals as per Kalle's suggestion. Cheers! On 09.09.2016 at 08:23, Matteo Beccati wrote: > I try to stay away as much as possible from persistent connections as > they can cause more issues than what they actually solve. I think I even > never used them on PDO. > > That said, yes that's the behaviour I would expect. Transactions should > be rolled back and the environment should be completely clean from > anything that's suppose to last for the current session only. > > > Cheers > > On 02/09/2016 14:18, Christoph M. Becker wrote: >> Hi! >> >> I wonder whether the shared behavior of persistent PDO connections is >> really desired, as it is implemented now. >> >> I stumbled upon this issue when I tried to resolve bug #63343[1] with PR >> #2112[2]. Nikita pointed out the actual problem, namely that destroying >> a PDO object will rollback the transaction on the inner object[3]. >> Digging a bit deeper brought up the issue that not only a transaction >> would be rolled back, but also that the persistent_shutdown() method >> will be called in that case. Consider the following script: >> >> <?php >> function foo() {return 1;} >> >> $db1 = new PDO('sqlite::memory:', '', '', >> array(PDO::ATTR_PERSISTENT => true)); >> $db1->sqliteCreateFunction('foo', 'foo', 0); >> >> $st1 = $db1->query('select foo()'); >> echo $st1->fetchColumn(); >> >> //$db1 = $st1 = null; >> >> $db2 = new PDO('sqlite::memory:', '', '', >> array(PDO::ATTR_PERSISTENT => true)); >> >> $st2 = $db2->query('select foo()'); >> echo $st2->fetchColumn(); >> >> The output is 11. However, uncommenting the line which >> will force the >> destruction of $db1, will also unregister the foo function, >> so the >> second ::query() will fail. This can be quite confusing in a more >> complex script. >> >> Furthermore, in php_pdo_driver.h pdo_dbh_request_shutdown >> is >> documented as[4]: >> >> | called at request end for each persistent dbh; this gives the driver >> | the opportunity to safely release resources that only have per-request >> | scope >> >> However, pdo_dbh_request_shutdown isn't just >> necessarily called only >> at the end of the request, as shown above. >> >> Anyhow, if the shared behavior of persistent connections works as >> intented, the documentation should be updated respectively (and bug >> #63343 closed as being not a bug). >> >> [1] <https://bugs.php.net/bug.php?id=63343> >> [2] <https://github.com/php/php-src/pull/2112> >> [3] >> <https://github.com/php/php-src/pull/2112#discussion_r77312340> >> [4] >> >> <https://github.com/php/php-src/blob/PHP-7.0.11/ext/pdo/php_pdo_driver.h#L279-L282> >> >> > >