What “Sleep” Means in MySQL

A Sleep process is a client connection that’s still open to the MySQL server, but not actively doing anything at that moment.
 
Think of it like a customer who’s sitting at a café table with their coffee cup but hasn’t placed a new order. They’re not taking up the barista’s time right now, but they’re still occupying a seat.
 
In SQL terms:
  • The connection is established.
  • No query is currently running.
  • It’s “idling” until the client either issues a new query or disconnects.

Why Sleep Processes Happen

  • Persistent connections: Some PHP apps (especially with mysql_pconnect) keep connections open rather than reconnecting for each page load.
  • Bad application behaviour: A script opens a connection and never closes it.
  • Slow clients: The client sends queries sporadically but holds the connection open the whole time.
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When Sleep Processes Are a Problem

A few Sleep processes are normal. But problems arise when administrators hundreds of them piling up on the server, these can include:
  • They can exhaust MySQL’s max_connections limit, blocking new queries.
  • They can hold onto memory unnecessarily.
  • They make the server feel “sluggish” because you’ve got too many idle but open sessions.

Why Sleep Processes Happen

  • Persistent connections: Some PHP apps (especially with mysql_pconnect) keep connections open rather than reconnecting for each page load.
  • Bad application behaviour: A script opens a connection and never closes it.
  • Slow clients: The client sends queries sporadically but holds the connection open the whole time.

Why Elementor (and page builders in general) Cause Sleep Processes

  1. AJAX-heavy editing

    • When you edit a page in Elementor, it fires off dozens of AJAX requests in the background to load widgets, templates, images, and save changes.
    • Each request can open a MySQL connection. If the script doesn’t explicitly close it (or if persistent connections are on), the connection drops into Sleep.
  2. Autosave and Revisions

    • WordPress autosaves drafts every few seconds while editing.
    • Each autosave = new write query to the database.
    • If the editor is open for a long session, that can leave a trail of idle connections.
  3. Poorly optimised plugins

    • Some Elementor add-ons query the database inefficiently (loading all templates, fetching every meta value, etc.).
    • If these queries aren’t closed quickly, they show up as Sleep.
 

What Clients Can Do (Specific to WordPress + Elementor)

  • Keep editing sessions short: Leaving the editor open for hours can accumulate Sleep processes.
  • Limit simultaneous editors: Multiple people editing pages at once = multiple idle connections.
  • Optimise the database: Use a plugin like WP-Optimize to reduce bloat from postmeta, revisions, and autoloaded options.
  • Disable persistent connections: In wp-config.php, make sure persistent DB connections aren’t being forced.
  • Check plugins: Some Elementor add-ons are notorious for database inefficiency. Disabling one can cut Sleep processes dramatically.
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