Category: WordPress | Page 2

Slow Posting Performance in WordPress 2.7

An interesting problem today – WordPress posting on this site was sloooooow. Some other back-end tasks were also incredibly slow.

Adding a post or page would take about 30 to 60 seconds. Unacceptable. I did the usual job of deactivating plugins, and even resorted to a different theme for a few minutes but no, it was all still very slow.

That’s when the work starts. On this server we haven’t opened up port 3600 to allow remote connection with mySQL Administrator, so instead it’s straight into phpMyAdmin.

The process is then pretty simple – for each table you have an Operations tab. Here you can see some information about the state of the table as well as quick links at the bottom to allow you to run various tools. The process I use is to backup the site then run a Repair then an Optimize on the _posts (typically tables are prefixed WP_) , _postmeta and _options tables.

Why the Slowdown?

Well, I didn’t bother investigating properly – without full server access it’s often hard to get full timings. You can put traces into code and look at logs, or you can very quickly run the Repair process. But what I do know is that databases can slow down for inserts more easily than for reads. This is usually because something’s become messed up in an Index, or the whole table’s become inefficiently organised over time. By repairing and optimizing you get to quickly tidy things up and restore the performance of the site.

For a minor site like this, it’s about the best approach to take. If you’re running something like Facebook you’ll probably want to investigate things properly – but then you’ll have the money to be able to do so as well!

Handy Tip for CSS Reloading

CSS not refreshing in the browser can be a pain – Mark Jaquith has come up with an elegant solution to this for WordPress coders.

I saw this rather handy tip on CSS reloading on Mark Jaquith’s blog today. Such a simple approach, but a great one for when you’re making CSS changes and need browsers to pick up on it immediately, rather than some hours down the line.

Some changes are critical. Now you can version your css by hand, but you don’t have to.

The basis of the change is to use the code:

<link rel="stylesheet" href="<?php bloginfo('template_url'); ?>/style.css?v=<?php echo filemtime(TEMPLATEPATH . '/style.css'); ?>" type="text/css" media="screen, projection" />

But for the detail, go read Mark’s post.

PHP Serialization Fix for WordPress Migrations (& other applications like Expression Engine)

Serialization of data loaded into an SQL table is a dreadful thing and makes WordPress migrations harder than they should be, but it happens and so we must deal with it. I’ve knocked up a rough and ready bit of code which does its best to resolve the problem.

When you move a WordPress blog from one folder to another, or from one site to another, you normally use the export/import functionality.

This is fine for normal blogs, but say you’ve developed a new website and set it up on your local machine – the URL for the site may be something like http://localhost/devsite and the live URL will be something like https://davidcoveney.com – you won’t want to set up all the theme options, site options, plugin options and so on all over again.

A different kind of migration - public domain from Wikipedia Commons — A different kind of migration – public domain from Wikipedia Commons

Instead, a theoretically simple approach is to do a database dump, a search and replace for all references to server paths and URLs, and then reimport that data in the new location.

Should work, but it often falls apart.

What happens is that in WordPress, its themes and its plugins, a lot of data is stored using a method known as serialization. Now, in my opinion this breaks all known good practice around data – it’s language specific, it’s not relational even though it often could be, and it’s hard to edit by hand.

One particular problem is that if you change the length of the data in a serialised string you have to change the length declared in the generated string.

That’s very painful when you have hundreds of the fields.

So, because I’d found this painful I decided to knock together a quick application to at least reduce the amount of editing I had to do. You just do your search and replace, forget about the serialized string lengths, upload your data to the new database, and run this script.

Warning: I haven’t got it to work for widgets and cForms II yet, but the latter has some export functionality anyway, which takes that particular pain away if you plan ahead. In the meantime, feel free to play with the attached file. You use it at your own risk, of course.

To use it, download the file linked in this post, extract it, open the file, edit the connection settings, tell it the table you want to scan through, the column, and the unique key field. If you somehow manage to have more than one unique key to deal with (you shouldn’t, but then it surprises me what people manage to code up), then you’ll have to modify the code accordingly. Once done, make sure you have a backup of that table, and execute the php – either at the command line or through the browser. License is WTFPL, and if you’d like to improve the code, please do and I’ll host the new version.

download file

Serialization-fixer.zip download

BIG WARNING: I take no responsibility for what this code does to your data. Use it at your own risk. Test it. Be careful. OK? Here in the North we might describe the code as being as “Rough as a badger’s arse.” Never felt a badger’s arse, but I’ll take their word for it.