Title: Critical Performance Issue wordpress multisite
Last modified: February 2, 2026

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# Critical Performance Issue wordpress multisite

 *  [georgecampos](https://wordpress.org/support/users/georgecampos/)
 * (@georgecampos)
 * [4 months, 1 week ago](https://wordpress.org/support/topic/critical-performance-issue-wordpress-multisite/)
 * WordPress 6.9 Multisite, subsite, Ultimate Member 2.11.1
   Hello. First off, I 
   want to express my appreciation for this excellent plugin. It has been a vital
   tool for our infrastructure, providing great functionality and flexibility. We
   heavily rely on it across our network.
 * However, we are running a large WordPress Multisite installation (1,000+ sites)
   sharing the global user tables, and we identified a specific bottleneck that 
   I believe could help you improve the plugin for high-scale environments.
   **The
   Problem:** The plugin executes a heavy `SELECT DISTINCT SQL_CALC_FOUND_ROWS` 
   query joining `wp_users` with multiple instances of `wp_usermeta` to filter users
   by `_um_registration_in_progress` and `account_status`.
 * Since the standard WordPress database structure does not include a composite 
   index for `(meta_key, meta_value)`, MySQL performs a **Full Table Scan** on the`
   usermeta` table for every check. In a large network, this causes:
    1. Massive I/O usage.
    2. Query execution times exceeding 100+ seconds.
    3. Table locking chains that paralyze the entire network.
 * **The Query Identified:**
 *     ```wp-block-code
       SELECT DISTINCT SQL_CALC_FOUND_ROWS wp_users.IDFROM wp_usersLEFT JOIN wp_usermeta ON ( wp_users.ID = wp_usermeta.user_id AND wp_usermeta.meta_key = '_um_registration_in_progress' )LEFT JOIN wp_usermeta AS mt1 ON ( wp_users.ID = mt1.user_id )...WHERE 1=1 AND (  ( wp_usermeta.user_id IS NULL OR ( mt1.meta_key = '_um_registration_in_progress' AND mt1.meta_value != '1' ) )  AND  ( mt2.user_id IS NULL OR ( mt3.meta_key = 'account_status' AND mt3.meta_value = '' ) ))...
       ```
   

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 * 0 replies
 * 1 participant
 * Last reply from: [georgecampos](https://wordpress.org/support/users/georgecampos/)
 * Last activity: [4 months, 1 week ago](https://wordpress.org/support/topic/critical-performance-issue-wordpress-multisite/)
 * Status: not resolved