Re: PHP and two phase commit transactions

On Tue, 29 May 2012 22:27:53 +0200, Christian Ferrari <camauz@yahoo.com> wrote:

These are the issues I partially solved integrating LIXA with PHP. 1. XA interface is a C level interface: the PHP database drivers must be changed at C source level to avoid many leaps between C and PHP code. The most important PHP database drivers are distributed with PHP core itself => patching their source code is equivalent to patch PHP core. 2. As a consequence of the first point, the LIXA PHP wrapper itself should be distributed with PHP core to avoid dependencies between some core extensions and an external extension. 3. The TX API does not deal with the concept of "connection" because it's implicit: every process/thread has its own connection with every Resource Manager (database). Better explained: tx_open(), tx_begin(), tx_commit(), tx_rollback(), tx_close() (and so on...) do not specify the handlers necessary to distinguish connection objects. 4. The TX API design does not take into account the concept of "persistent connections" and "connection pooling". I afforded issues 1 and 2 creating a global experimental patch for PHP core itself (you can find it in "ext/php" directory of LIXA tarball or directly at SVN repository. http://lixa.svn.sourceforge.net/viewvc/lixa/ext/php/). Issue number 3 was bypassed and, for the sake of trivial "hello world equivalent examples", the integration seems to work properly. Issue 4 is quite difficult to address: I ignored "persistent connection" disabling LIXA feature when the application asks a persistent connection, but I was not able to deal with Oracle "connection pools" of oci8 driver.

I have some concerns about the approach you're taking. I don't think a compile time dependency to LIXA is acceptable. Can't you add some hooks to the several database extensions? From a glance at your patch, it seems you only need to change the behavior when getting a new connection and closing one. This shouldn't be much work. Once that were done, one would be able to plug the LIXA extension (or any similar extension). I don't think this approach would get objections from the extension maintainers and it is more versatile. -- Gustavo Lopes