One of the best advantages WordPress offers is that the application can easily be extended thanks to the number of the free plugins available on the official repository. This however, hides risks. The installation and activation of too many plugin may increase the resource consumption of the application which might be penalised by the hosting service provider. Before proceeding with the installation of any specific plugin, it would be good to put it on test on a local environment and check how it works. Before publishing to live, make sure you have a backup copy to revert. The same goes to themes as well. There are a number of themes published on the official website. Some of them are indeed professionally developed, but of course there are some with coding issues that may cause troubles.
Speaking of resource consumption, I would like to highlight 3 main aspects of the problem.
- Memory usage
- CPU usage
- and Mysql issues in a form of slow queries
As these 3 are separate issue which is some cases could be connected, they require different approaches to resolve.
WordPress memory usage
The error that refers to insufficient memory is “Out of memory …” either displayed on the home page or on a specific inner page. WordPress triggers it when the maximum amount of memory is reached and there are not enough resources in order to complete the request. So the question here is how to resolve this.
Generally speaking there are a number of methods that would give positive effect over the memory usage. The main ones are :
- Remove the plugins you do not need. I can assure you that WordPress does not need 20+ active plugins in order to operate normally.
- Upgrade PHP Version. Note that newer PHP Versions are better optimised and this way decrease the resource consumption. For example PHP4 compared with PHP3 consumes over 45% less memory. So if your hosting provider supports multiple PHP version, I would recommend migration to newer version.
- Another available course of action is of course adding more memory. This depends on the situation. If the website is less known and the problem is caused by a number of plugins which are not actually needed, then upgrading the memory may not be wise.
- Perhaps the best solution is going further and investigate what exactly is the root of the problem. There are a few great plugins that would help to measure the usage and pinpoint the top consumer. Such investigation requires a bit more skills and if you are new on the field, you may need help from experienced developer. Plugins that give better idea on which plugin consumes the majority of the resources are P3 Profiler; Memory Viewer and Debug Bar.