[Phpmyadmin-devel] #4536 - master: import problem (PMA_String)

[Marc Delisle]

Le 2014-09-25 16:16, Hugues Peccatte a écrit :
> 2014-09-25 22:02 GMT+02:00 Marc Delisle <marc at infomarc.info
> <mailto:marc at infomarc.info>>:
> 
>     Hugues Peccatte a écrit :
>     > 2014-09-25 20:08 GMT+02:00 Chirayu Chiripal
>     <chirayu.chiripal at gmail.com <mailto:chirayu.chiripal at gmail.com>>:
>     >
>     >>
>     >> On Thu, Sep 25, 2014 at 12:17 AM, Hugues Peccatte <
>     >> hugues.peccatte at gmail.com <mailto:hugues.peccatte at gmail.com>> wrote:
>     >>
>     >>> 2014-09-24 14:42 GMT+02:00 Chirayu Chiripal
>     <chirayu.chiripal at gmail.com <mailto:chirayu.chiripal at gmail.com>>:
>     >>>>
>     >>>> I was just wondering what will be the effect if we make current
>     methods
>     >>>> as static in those classes?
>     >>>>
>     >>>> --
>     >>>> Regards,
>     >>>> Chirayu Chiripal
>     >>>> https://chirayuchiripal.wordpress.com/
>     >>>>
>     >>> It's almost the same thing to use a static or a non-static
>     function. This
>     >>> is 2.5x slower than standard PHP function.
>     >>>
>     >>> See:
>     >>> Time: 1.7506999969482 //standard PHP function
>     >>> Time: 4.3722500801086 //object
>     >>> Time: 4.3722498416901 //object with static function
>     >>> Time: 3.6722099781036 //PMA function, even this one is 2x slower
>     than
>     >>> standard PHP function…
>     >>>
>     >> Are these tests performed on mb_* function or non mb_* one?
> 
> 
> I forgot to answer to this question…
> So the tests are with non mb_* functions.
>  
> 
>     >>
>     >> One thing is clear from these results is that even wrapping a
>     built in
>     >> function in another function (wrapper function) has some significant
>     >> overhead. And using OOP/Classes is like wrapping that wrapper
>     function
>     >> further into a another wrapper causing further slowness. So why
>     not just
>     >> use mb_* function directly everywhere? If we do this, then what
>     to do in
>     >> case mb_* functions are not available? Maybe we can just define a
>     new mb_*
>     >> function to use respective non mb_* function for it. For e.g.
>     >> // Define a function like this
>     >> function mb_strlen($str) {
>     >>     return strlen($str);
>     >> }
>     >> // or create an alias of strlen() as mb_strlen() (I heard this is
>     possible
>     >> in PHP 5.6+)
>     >>
>     >> By doing this, we can get speed advantage of built in mb_* function
>     >> whenever it is available by avoiding any wrapper function or
>     class. And in
>     >> cases where it is not available, a wrapper function with standard
>     non mb
>     >> function can deliver equivalent performance as non mb function is
>     >> inherently faster than its mb_* mod.
>     >>
>     >>
>     >>> Hugues.
>     >>>
>     > Hi,
>     >
>     > This is a very good idea!
>     >
>     > Marc, you asked to create PMA_* string functions. Do you agree
>     with the
>     > Chirayu's proposal? So we won't have PMA_* functions, but only mb_*
>     > functions.
>     >
>     > Hugues.
> 
>     I have not followed the latest test results in this thread. If it's true
>     that using wrappers has a big cost, I am in favor but I fear that people
>     reading the code do not realize that the mb_* function could be a
>     wrapper.
> 
>     Not sure how to document this.
> 
>     --
>     Marc Delisle (phpMyAdmin)
> 
> 
> Using wrappers, the time could be doubled.
> So with his proposition, the wrappers would be created only when mb_*
> doesn't exist.
> If mb_* exist, we won't redefine it, but the execution would be slower
> because mb_* are slower.
> If mb_* don't exist, the non-mb_* functions would be wrapped, so will be
> a little bit longer than without wrap.
> And we would also be able to force the use of non-mb_* functions if needed.
> 
> As you said, the only thing that might be difficult, would be to
> document the fact that mb_* functions could be pMA functions. We should
> choose between clarity and "performance".

Performance should have priority, but maybe we can have both. I assume
that the changes will be done automatically, so what about introducing a
small PHP comment at the same time?

Something like this:

(before)
if ($pmaString->strlen($db)) {

(after)
if (/* overload? */ mb_strlen($db)) {

-- 
Marc Delisle | phpMyAdmin