query profiling support

[faulkner]

I'd like to be able to profile queries in ways similar to Zend_Db and Doctrine.

Was going to just pipe the logger though Zend_Db_Profiler, but the logging calls are made before variable substitution (a bug in itself, IMO).

[jpfuentes2]

We're using PDO prepared statements which means we don't have access to the SQL generated w/ values @ logging time. The only way to get around this would be to add substitution to the SQL prior to logging. Would you like to take a stab at this?

[greut]

I've managed to to something of that flavour:

https://github.com/greut/php-activerecord/compare/gh133-profiling

How the values are serialized could be improved if any of you have a better idea.

[faulkner]

@greut, nice! Haven't had a chance to give it a try, but that's about what I was thinking. Not too concerned about the values as long as they're in included; it's enough to reconstruct the queries later.

Another option would be allowing the user to throw in some kind of shim in the vein of http://daveyshafik.com/archives/605-debugging-pdo-prepared-statements.html, which would keep the project code from getting too bloated with extra conditionals. I didn't find a good way to roll that in without patching Connection.

[greut]

@faulkner PHP ActiveRecord uses only ? which aren't supported. Maybe ActiveRecord\Expressions::stringify_value() can do better. Let's see if someone from AR comes around :-)

[greut]

I've added some tests on the logging which wasn't tested.

[nakashu]

Can this be merged to master ?

[jpfuentes2]

@nakashu I'm not 100% certain on its current manifestation. If @greut can answer my question about the exception handling changes then we probably can.

[jpfuentes2]

Closing this as a dup of #363