Comments on: Caching PHP objects: how to do it in 4 easy steps

By: phil

phil — Wed, 04 Jun 2008 14:12:10 +0000

@Jeff: I love your inquisitive mind and your educated guess is very warm but it isn’t quite correct. I’ll be posting more details about the top secret web app in the future.

By: Jeff

Jeff — Wed, 04 Jun 2008 11:43:24 +0000

Nice article Phil. Joe Nobhead, haha!

I’m gonna hazard a guess that this is some sort of content management system?

By: enzo

enzo — Sun, 01 Jun 2008 18:53:02 +0000

fs cache sucks by default,
try memory storage

By: karuna

karuna — Sun, 01 Jun 2008 10:48:34 +0000

i like the article… but the yellow… hurts after a while but if you like it well go ahead.

By: josh

josh — Sat, 31 May 2008 18:32:24 +0000

Thanks for saving the internet a few microseconds

By: phil

phil — Mon, 26 May 2008 13:36:15 +0000

@Chris Gibson: In terms of benchmarking all I’ve done is to use microtime() at the start of each page (on the website) and than at the end of each page convert that figure into the number of seconds it has taken to load the page.

An average(ish) figure is that for the site homepage, the load time was around 0.24 seconds and with the caching in place it became around 0.06 seconds. It also reduced the number of MySQL queries from 77 to 7.

It’s worth pointing out the the reason for all these (77) queries was a number of recursive functions used to work out menus and see if certain pages were children of other pages. I haven’t used the caching as a way to speed up objects but rather, as a way to reduce the number of times each page calls the database. I’m not sure how effective my method would be as a way to simply cache an object that makes no use of a database.

By: Dominik

Dominik — Mon, 26 May 2008 10:35:26 +0000

@Daron, Drew and phil:

Actually Memcache is not so fast after all. I did some benchmarks of various “caching techniques” and was quite surprised that using the hard-disk for caching was considerably (about 30%) faster for reading and about 600 times faster for writing (in a local machine/one machine environment).

Either I did something terribly wrong with my benchmarks, or I’ll probably go with using a Filesystem RAM-Disk for caching (haven’t tried it’s performance, yet).

By: Dan

Dan — Sun, 25 May 2008 19:31:03 +0000

The yellow… it’s burning out my eyes!

By: Chris Gibson

Chris Gibson — Sun, 25 May 2008 18:38:11 +0000

Good article. I’d be very interested to see some benchmarks that quantify the benefits of this caching method; are these available?

Also, this is nitpicking somewhat, but the “removeHours” function could perhaps be considered redundant. The standard strtotime function will interpret relative time descriptions, so you could just write:

strtotime(’-1 hour’);

… instead of removeHours([date], 1). To specify the start date, you’d write strtotime(’-1 hour’,strtotime([date])) or similar.

See: http://uk.php.net/manual/en/function.strtotime.php

By: phil

phil — Sun, 25 May 2008 14:26:34 +0000

Thanks for everyone’s comments and suggestions. Drew, that is exactly what I was after.

I’ll be sure to check out Memcached, as recommended, but I’m not sure it’ll be applicable to my particular situation.

@Brant: The example I give can quite easily be changed to not use a ‘.inc’ extension, you could use anything you want.

@Drew: I try to namespace my cache files for the exact reasons you mention. It’s easy to loop through a directory and then delete all files with that namespace if required. Sadly, this web app won’t be able to make use of cron jobs (in most cases) but otherwise it’s a good approach and I’ll definitely check into using the /tmp file as the repository.