High CPU Usage (100%) Caused by Ultimate Membership Plugin

Hi there,

I’ve been using the Ultimate Membership plugin on one of my client’s websites for a long time. Recently, we noticed that the website/server goes down due to 100% CPU usage. When I contacted the Cloudways support team, they mentioned that the issue is caused by the Ultimate Membership plugin.

Below is the email summary from them. Please note that I am using the latest version of Ultimate Membership on the client’s website:

• Multiple long-running MySQL queries were detected, with execution times ranging from 280 to 374 seconds.
• These slow queries are executed repeatedly (over 90 occurrences) and primarily involve the following tables:
  • wp_posts
  • wp_term_relationships
  • wp_postmeta
• The queries are associated with content restriction logic (um_content_restriction), strongly suggesting the involvement of the Ultimate Member plugin.
• Extensive LEFT JOIN, GROUP BY, and ORDER BY operations on large tables are causing significant database load and request blocking.

Root Cause: 
The Ultimate Member content restriction queries are inefficient and lack proper indexing, resulting in repeated full table scans on wp_postmeta and taxonomy tables. This considerably slows page load times and increases server load.

Recommended Resolution:

1. Review the Ultimate Member plugin:
   • Disable or optimize content restriction rules if they are not necessary.
   • Ensure the plugin is updated to the latest version, as older versions are known to generate heavy queries.
2. Database Optimization:
   • Add appropriate indexes on the following:
     • wp_postmeta (post_id, meta_key)
     • wp_term_relationships (object_id, term_taxonomy_id)
   • Remove unused post meta entries related to um_content_restriction.
   • If necessary, temporarily disable the plugin to verify its impact.

Do you guys have any idea how we can resolve this? Looking forward to hearing back from you guys.

Thank you!