PHP Caching Scripts

[piper]

Are PHP caching scripts available through any of the VPS control panels? I wanted to install one but was wondering if an easy click and install option was already avaialble. Thanks.

[Eric]

Are you curious if something like mmcache is available as a one click install? I'm not 100% sure what you mean.

[Gwaihir]

Yep, I think that's what she's asking. APC seems to be the up and coming one btw. They're even currently considering including it in the standard distribution of PHP.

[piper]

I wanted to install eAccelerator. I noticed Zend Optimizer is already running. Do I need another PHP caching script or is Zend Optimizer sufficient?

[Gwaihir]

Sufficient depends on what performance you have / need. Zend Optimizer is not a chaching script. It optimizes another step of the process and can be run alongside a byte chache of your choosing.

I've used eAccelerator on an intranet server with PHP 5.0 myself and that worked fine. I had to stop using it though when I upgraded PHP to version 5.1. If you wish to use it for PHP 5.1 do have a good look around first to see if the (well known) problems it had with that version have been resolved (or just go with APC instead).

[tank]

Have you guys gotten APC to run on the VPS's running on centOS? I have had a headache trying to get it up and running. I used eAccelerator as well up till I upgraded to PHP 5.1 and then had the same issues that everyone else is seeing.

[Vin DSL]

Out of curiosity, why are you 'guys' caching your sites?

I run a flat file cache for Open Directory Project search results, on my site, but it's out of necessity. If you hit ODP too frequently, it starts throttling you back, so to speak -- like some sort of flood control, or whatever. The more you hit ODP, the less responsive it becomes, so, I cache the results for a week.

To tell you the truth, other than situations like the above, I've never understood why webmasters want to serve stale pages, and so forth, from a cache.

On top of that, caching your site is sometimes highly undesireable, e.g. you have to be very careful what you cache and what you don't. If you cache everything, usually your site will get all jacked up. Moreover, when you start 'un-caching' the stuff that shouldn't be cached, there's usually no speed benefit, et cetera, so I don't get it...

[Ron]

I think they're talking about code caching, Vin.

[jason]

Yes, these packages cache PHP code in a compiled state so that scripts can run faster. They don't cache the actual content of the pages (unless its embedded in the code, of course).

--Jason

[Vin DSL]

Yes, these packages cache PHP code in a compiled state so that scripts can run faster...

Hrm... Maybe I didn't ask the right question...

With all the latency involved, serving PHP web pages on the web, especially on a $10/mo. shared hosting plan, what friggin' difference does it make?

[tank]

yes. it brings the overall apache server load down due to teh code allready being compiled and stored. It actually works very well on a busy site. On one of the ded boxes that we run the stats are around 1200 cached files and around 30 requests per second. It reduced the overall load by about 1/4. that is using APC on Fedora. I still can't get it installed on CentOS.

The papers I saw on PHP6 say that APC is coming bundled in the package.

[tank]

With all the latency involved, serving PHP web pages on the web, especially on a $10/mo. shared hosting plan, what friggin' difference does it make?

you're in the VPS forum Vin

see my numbers above

[Vin DSL]

you're in the VPS forum Vin

see my numbers above

Heh, sorry! My bad!

Carry on!

[Gwaihir]

With all the latency involved, serving PHP web pages on the web, especially on a $10/mo. shared hosting plan, what friggin' difference does it make?

I suppose that's for JagPC to answer. I don't think they've got it installed on the shared servers, so I suppose they agree with you on that one.

Personally, I suspect it works best on a server that sees a lot of hits on a relatively small percentages of the available pages. I doubt that's the case on the average shared server.

Why? Because the cache isn't endless and the caching itself takes time too. IIRC my tests on PHP5 + eAccelarator showed something like this. Requesting a page for the first time cost 130% of time PHP only would take. Requesting the same page again took 40% of time PHP only would take. Of course, much can no doubt be done by tweaking the settings, but the point remains: if you see hits predominantly on a handfull of pages, byte cache is great, especially if you can allocate memory to it (not just disk space), but if your hits are widespread, you'll have a lot of fine tuning to do for what probably ends up as a minor speed gain only. You'll have to invest a good deal of diskspace for that and you'll be juggling optimal settings for memory use over a number of caches fighting for it, as there's not just the PHP byte chache that would like it, but other caches such as a disk cache and MySQL's cache as well.

[piper]

Just installed eAccelarator. It wasn't as hard as I thought, the instructions were clear. Anyhoo, I notice a big difference in page loading time. Thanks.