In my opinion, Revisions in WordPress are a waste of time. I don’t know anyone that actually uses them - and worse, they can have a serious impact on site performance, especially in the admin area.
Revision Management Deleting: There is an API function to delete revisions, but there is no UI. That can certainly change. WordPress Codex, Revisions
Personally, I find this ridiculous - it means that for the average user every time a post is updated the database gets a bit more bloated - and there is no UI to remove this bloat.
When to be Concerned
You may hit a 500 server error when trying to access an edit page for content that has a lot of associated revisions.
Editing a reasonably sized page with hundreds of revisions can cause problems, even with 256MB server memory available. This trac ticket outlines the problem nicely. I had to deal with this exact scenario today, which prompted this post.
Enabling error logging may give you a message like this:
…you’ll find a similar message in your Apache logs.
Increase Available Memory
This is a band-aid solution, but increasing the available memory can provide an instant fix, and buy some time. Under Ubuntu, edit
IMPORTANT: Restart Apache for the changes to take effect. You could also add a directive to a
.htaccess file if you’re using one, or add a directive in an Apache virtual host configuration.
Now that the client has stopped panicking, you can fix the real problem: Revisions.
TLDR; Delete Revisions
You need MySQL access to delete revisions.
Get a MySQL command prompt, using your target database:
Unfortunately, it’s not quite as simple as just deleting posts from
wp_posts table having a post_type of ‘revision’ - you should also remove associated postmeta and wp_term_relationships records.
You can achieve this with the following MySQL/MariaDB commands:
This command deletes records from tables a, b and c - defined as wp_posts, wp_term_relationships and wp_postmeta. The rows deleted are determined by these criteria:
- Rows in wp_posts table which have a post_type of ‘revision’
- Rows in wp_term_relationships which have an object_id equal to the ID of a wp_posts ‘revision’ row.
- Rows in wp_postmeta which have a post_id equal to the ID of a wp_posts ‘revision’ row.
For a custom agency build with a lot of custom fields, number 3 is likely to be a big one. For each revision saved, WordPress will add a new postmeta record for each custom field.
Limit revisions to a rational number, or prevent them altogether - add this to
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