HTTP requests start hanging after I try activating all plugins, and only stop when I manually disable the plugins via DB

Are you checking the slow query log in mysql or connection count? Just off the top of my head I would say mysql might be choking on something. Also, top can show you which processes are going crazy when this happens.

Here is a bit on the slow query log and different ways to access its information:
https://rtcamp.com/tutorials/mysql/slow-query-log/

Related Posts:

  1. What happens when wp_cron is deactivated in WordPress?
  2. How to solve a conflict between a plugin and a theme?
  3. How do I change the description of the same image which is to be found in multiple instances?
  4. Server configuration for WordPress – Do I need install PHP-SSH extensions for WordPress on Fedora28?
  5. Masonry images not working
  6. WordPress continually requests pages from itself
  7. My WordPress website was hacked [closed]
  8. I can’t change permalink in WordPress 4.5.3
  9. Plugins & backup not working correctly on new Digital Ocean server
  10. How to reduce Apache connections caused by plugins?
  11. Check against server time to display SQL entries – Radio Station DJ Rotator Plugin
  12. Plugin error after installation
  13. Custom WordPress feed on Apache server returning 304 response for if-modified-since
  14. the content of the uploads folder gets deleted periodically, how to figure out what causes it?
  15. Multiple wordpress installations with same plugin folder (Apache Virtualhost)
  16. URL Rewrite 404
  17. Why my multisite is this slow? (stats inside)
  18. Is there going to an issue running different features of WP site in different subdomains?
  19. W3 Total Cache Can’t Really Detect Things
  20. Where to find remaining Boldgrid code in WP database?
  21. True or False: Is an Apache error or PHP error the same as a WordPress error?
  22. How can I disable a plugin in Health Check mode if there’s a critical error?
  23. Iframe beeing removed when embeding a video through block in Sensei LMS (Vimeo)
  24. Updating post_parent caused the website to become unresponsive for 40 seconds or more
  25. 403 forbidden error in the admin panel as well as on the admin-ajax.php file
  26. Help Needed: Issue with Change Permalink on DirectoryPress Listing Pages
  27. Shortcode Attributes to Return different $_POST
  28. How to find out which plugin create captcha after login?
  29. Comment IP Plugin – Fixing onfocus=’this.select()’
  30. How do I make reusable content blocks for header and footer when using WordPress headless with another front-end?
  31. WordPress 5.4 – How to prevent to enter only certain values in custom field
  32. What form should the $query media query array have for an Elementor page builder function? [closed]
  33. Private Page View Counter
  34. WooCommerce: Force coupon for existing/registered customers [closed]
  35. Plugin Activation Error – The plugin generated 22 characters of unexpected output during activation
  36. Plugin Admin Menu Boiler Plate
  37. How can I add IP address to my post?
  38. REST API can’t get the response manually
  39. Super slow plugin page (lots of error 500)
  40. How to make a dynamic css class whose name changes every visit to confuse scraper
  41. serverSideRender does not render “preview” html inside Gutenberg block
  42. How use wp media upload liberary in react components?
  43. Add_rewrite_endpoint doesn’t work with post name permalink structure
  44. How to notify wordpress instalation about my plugin update?
  45. Is it possible not to load theme on a specific page in wordpress?
  46. How to change shortcode’s default theme?
  47. Integer in Array returns null
  48. Plugin onclick button activate other plugin
  49. composer not working on my plugin when i upload it to my website
  50. wc_get_template new template does not showing up
  51. How to select a paragraph other than the 1st to be the post’s excerpt?
  52. Moving Jetpack buttons to appear below the first H2 title on all project/post pages [closed]
  53. Send email to multiple addresses on Contact Form 7, but exclude personal details on all but one
  54. How can I support plugins in a custom theme?
  55. Display site language setting in source code
  56. Show icons or badges under title on product archives/category pages
  57. How to get theme’s info from wordpress.org/themes using api.wordpress.org?
  58. Override/ignore CSS from active theme as not to interfere with my custom CSS
  59. WordPress Custom Pages that work with Plugins?
  60. posts from multiple post types in one slider
  61. How to automatically redirect to custom admin menu after plugin activation?
  62. How to use the CSS of the WordPress core in the development of my administration page?
  63. Redeclare function after plugin activation
  64. add_submenu_page returns null
  65. What is the WordPress approach to custom data?
  66. Conditional Shipping Options if Certain Products are in Cart WooCommerce
  67. Readable titles in mobile
  68. How to do the simplest possible frontend ajax call from a plugin?
  69. The XXX plugin has been deactivated due to an error: The plugin does not have a valid header
  70. How can I add “last updated” in plugin descripton?
  71. get_edit_post_link() not working on wp-cron
  72. get_option / wp_localize_script Not Working in OOP Plug In
  73. New bulk action to resend welcome emails
  74. Get site url and updates data, then use them
  75. How to have a gallery in which each image’s caption is a whole “post”?
  76. I receive taxonomy id
  77. How do we update a custom file upload field with the Advanced Custom Field plugin?
  78. WordPress won’t allow for updates to plugins or WordPress Core
  79. WordPress Stock Update Programatically
  80. Loading a plugin’s js file from functions.php
  81. Woocommerce Backend Search by Title and SKU
  82. I Setup Rate My Post Plugin On Site But Now Got Issues In Google Webmasters
  83. How to integrate together a website currently hosted WordPress.com and a custom web application currently hosted on Azure?
  84. How-to: This block can only be used once
  85. output html on post or page from custom plugin [closed]
  86. Custom Post Type – custom form in dashboard
  87. Problem with add_action
  88. To perform the requested action, WordPress needs to access your web > server
  89. Custom API plugin to execute 3rd party API to retrieve data
  90. Is there a way to convert shortcodes to html content?
  91. Proper way to handle admin-ajax calls
  92. How to display the featured post on the category page?
  93. Disable globally “Crop thumbnail to exact dimensions (normally thumbnails are proportional)” with Multisite
  94. How to find the list of custom post type where logged in user is author
  95. UTF-32be error WordPress
  96. Loop in elementor custom widget not working
  97. Change text string in a plugin
  98. Set Multiple Meta Values as an Array Using dispatch( ‘core/editor’ ).editPost() Call in Gutenberg/JS
  99. wp-admin send 404 error
  100. How to create plugin/ page that reads from database
Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)