Plugin slows down my site

Hello, thank you for trying out BWP Minify!

First of all, please give this article a read: https://betterwp.net/wordpress-minify-javascript-css/

Have you tried enabling the friendly minify url feature? If you have a lot of javascript/css files, it’s best to build the cache when the site is idle (perhaps at night) using methods described in the article above.

Thanks! That was a great read! Finally I somewhat understand why I’ve had problems. I just woke up here where I live, and I just did a speedtest, and it is a lot faster now, and all the minify files take no time at all to load anymore.

(EDIT) I just removed a plugin and emptied the page cache, and afterwards the minify files began taking more time to load again. Am I correct in assuming it’s all about giving it the time to be cached properly before it gets fast again?

If you wouldn’t mind, could you have a quick look at my site to see if there are any critical elements that needs to be sorted, and point me in a direction in how to solve it? Google PageSpeed tells me there are lots of things wrong with my site, but it lists a lot of tings that I thought I had taken care of, such as minifying.

Thanks!
Havard

Am I correct in assuming it’s all about giving it the time to be cached properly before it gets fast again?

You are correct, it’s the same case for any cachable assets.

Sometimes PageSpeed’s reports are just misleading. I believe the main issue with your site is that you have too many plugins installed, like carrying 4 people on a motorbike, it will certainly be slower.

The best tip I can give right now is to pre-minify and split the minify string into smaller strings (try 7 or 5 files per string). Pre-minify is probably the most efficient, however not a straightforward approach.

Something of note that I found through testing:

The plugin is really slow if your host is using php 5.4 or below, whereas if you’re using php 5.6+ it doesn’t seem to have any of these issues.

I suspect this is mainly due to the new Zend Opcache code that is present in php 5.6 and up.

FWIW: Rough values for a site I tried it on were:
6.5-7 secs without bwp (php 5.4)
30+ secs with bwp (php 5.4)
5.5-6 secs without bwp (php 5.6)
4.5-5 secs with bwp (php 5.6)

@cefiar Opcode cache is not used by default by the Minify library, so I don’t think it’s the reason here. I do have tests that are run in a PHP 5.4 environment, and I don’t see any noticeable slowdown. Have you tried “ignoring” files one by one and see which one is the culprit? Also, is it slow (30+ secs first time) for both CSS and JS files?

After a further bit of testing I’m pretty sure this is down to PHP free memory. Without the Zend Opcode cache, PHP uses a lot more memory. I think this mainly just slows down stuff as things process in smaller chunks, freeing memory, then using it again.

FWIW: The part of the page that was taking the most time (most of the 30+ secs was the main WordPress home page (the HTML output from the site root). To me, this implies this delay was either:

1. All the changes to script and style enqueuing, which of course includes interaction with all plugins, themes, etc (and their memory usage requirements).
2. Any post-processing of the HTML output (eg: compression, etc).

Note: I still found this fairly true with most of plugins disabled on my site too, so #1 doesn’t seem to be quite so likely. At that point I backed off since it wasn’t getting me anywhere and I needed the site working. I upgraded the host to PHP 5.6 and since then, everything is fine with BWP active. I suspect I could debug this more by disabling the Zend Opcache in php 5.6 (for testing), but I’ve got a few other things I need to work on that have slightly higher priority ATM.

OK thank you @cefiar, if you find out anything else please let me know.