Uncached functions
Some functions in WordPress Core are purposely uncached, and will always result in an SQL query when called. This can have performance implications for a site.
Tag: tech-ref
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Object cache
The WordPress object cache is the second layer of caching that is encountered by requests that pass through the page cache and are routed to the origin servers. The object cache stores common or expensive operations directly into memory so that subsequent requests can quickly access them.
Responsive images
Responsive images are automatically supported by WordPress Core. Image markup will automatically include srcset and sizes attributes for images uploaded to a WordPress site’s Media Library. These attributes enable web browsers to automatically use and display the most suitable image size based on a device’s screen size.
Intermediate images
By default, a set of alternate sizes are generated for images that are uploaded to a site’s WordPress media library. These alternate sizes are referred to as “intermediate images”. WordPress Core defines a default array of intermediate image sizes: thumbnail, medium, medium_large, and large. The pixel dimensions for each of these default sizes can be defined in the Settings –> Media screen of the WordPress Admin dashboard.
Image file behavior
Default behavior of image files (e.g., jpg, png, gif) that are located in a site’s /uploads/ directory, served by the VIP File System:
Working with the /tmp directory
The system temp directory (/tmp) is a local, writeable path on an application’s web servers on the VIP Platform. The /tmp directory is most commonly used to perform local manipulations to temporary files. For example, transferring a ZIP archive to /tmp, extracting its contents, then uploading the contents to the WordPress site’s wp-content/uploads/ directory on the VIP File System.
Working with uploaded files
On most platforms, media files uploaded to a WordPress site are stored in a filesystem local to the site’s web server. On the VIP Platform, media files uploaded or imported to a WordPress environment are stored on the VIP File System, which is an external object store. A WordPress site’s /wp-content/uploads/ directory is mapped to this external object store. This design provides better security and allows VIP’s CDN to more easily scale access to a site’s media.
WP-Cron
VIP’s cron infrastructure leverages WP-Cron provided by WordPress Core, and cron jobs are initiated and regulated by Automattic’s Cron Control plugin. VIP’s Cron Control provides an optimized SQL table for WordPress Cron events. This approach satisfies the highly concurrent querying commonly seen on VIP sites. Each named event in the queue is handled in parallel with other events, allowing for a large event handling capacity. The VIP cron system orchestrates the activity of the event workers in the different containers, to avoid conflicts with two workers processing the same event.
New Relic
New Relic is an application performance monitoring (APM) tool used to monitor the code and browser performance for WordPress environments or for Node.js environments. New Relic is an Integration that can be added to an organization then activated on any application environment.
VIP Dashboard
The VIP Dashboard is a portal for application management, and for users to interact with the WordPress and Node.js VIP Platform environments that belong to those applications.