How to enable Redis object caching

Step 1 — start Redis

1. Open your Pressy and go to PHP in the sidebar.
2. Open the Caching tab.
3. Switch Redis object caching on.

Takes a couple of seconds. Nothing on your site changes yet — this makes a Redis server available, it does not make WordPress talk to it.

Step 2 — install the plugin

WordPress does not use Redis on its own. On the same screen:

1. Press Install Redis Object Cache. It installs switched off.
2. Press Activate the plugin.
3. Copy the host and port shown on the screen.
4. Open the plugin's settings in WordPress and enable the object cache there, using those values.

Press Open plugins in WordPress to get to the plugin in one click.

Checking it worked

The Redis Object Cache plugin has its own status page in WordPress and will tell you it is connected. That page is the one that knows — it reports from inside WordPress, where the caching actually happens.

Is it worth it?

Redis helps most on sites that ask the database a lot of questions: shops, membership sites, anything with many plugins or thousands of posts.

On a small brochure site with page caching already in place, the difference is hard to notice. OPcache, which is on by default and needs nothing from you, does most of the work on sites like that.

Redis uses a little of your memory allowance. You can see the effect on the health panel on your Pressy's overview.

Turning it off

Switch it off on the same screen. WordPress falls back to the database straight away. Deactivate the plugin as well, or it will keep looking for a server that is no longer there.