Mailinglist Archive: opensuse (908 mails)

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Re: [opensuse] apache 2.4 performance issue / processwire.
On 2016-06-09 10:08, Knurpht - Gertjan Lettink wrote:
Op woensdag 8 juni 2016 18:23:33 CEST schreef Per Jessen:
The developer claims the site serves fine on his own PC (typical
multi-core thingie)

And he has developped for a single user website on an equivalent of his PC ?
If he's a real webdevelopper he should know that his claim is useless.

This is about how I work:
- development environment locally. Using just a small amount of the data
- test environment, using the full data collection, stress testing should be
included ( what if X users hit the URL and trigger query Y to run ), needs to
be on (preferably) an identical machine.
- production environment, where only stuff lands that has proven to result in
a proper working situation.

Things I've seen where developers / designers claimed "it was running OK on
their machine" :
- MySQL databases with no indices ( works fine locally with 2 customers, 10
products, 10 orders )
- Huge queries that should only run for logged in users, but placed outside
the closed parts of the site
- Badly writen queries ( with OK results .... easily done )
- Calls to external webservices being left out

In my experience apache and nginx are hardly ever the cause of websites
running slow. Too many high res pictures can be one, but most modern CMS's
have their own caches, where they keep resized images, some even reduce on the
fly when uploading pics. Most of the issues in the performance area I've seen
are related to queries. The amount of attempts to "load everything we need in
one query" .... sigh.

I agree with the things that you say but as I understand Per's situation, they don't fit his symptoms.

His problem on the production system apparently occurs with a single user making a single request - the first request. So the problem isn't load-related or complex-query-related.

Per, various suggestions:

I do think you need a test system (the customer should pay really).

I think asking a question on the processwire forum might well be useful.

I think it would be useful to understand the difference between the developer's system and the production/test system. Can you or he run exactly the same strace test on his machine and get the same behaviour? If not, what is different?

I'm not a PHP programmer and knew nothing about processwire (though I do know Perl). There seems to be a debugger for PHP called xdebug, and it seems to be possible to run processwire from the command-line, which makes using a debugger much easier. So if it was me, I would try to run the same request that you used for the strace from the command line with the debugger and single step it to find out where the lstat's are happening.

HTH, Dave
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