[Solution] WordPress Admin Panel very slow after Updates (Case-study)

Recently I updated many of my sites to WordPress 3.9.1. To my astonishment, the edits, saves, deletes in WordPress Admin Panel were very slow. Initially I thought that my Internet connection must be slow. So I checked some other sites like yahoo.co.in which I visit frequently. They were fast. Since I was using shared hosting on HostGator, I thought there was some server problem.

So I contacted my HostGator support. I used both email and ticket support.

HostGator.comHostGator
Ticket: PBN-28928813
Hello there,

Thank you for contacting HostGator! I understand that you are seeing slow loading speeds for your WordPress admin area in regards to moving posts to the trash. While investigating this issue I found some fragmentation in your database which may be contributing to this issue.
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shreen11_tech.wp_commentmeta is 96.77% fragmented.
shreen11_tech.wp_comments is 75.66% fragmented.
shreen11_tech.wp_links is 100.00% fragmented.
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I’ve optimized your database’s disk usage which should speed up queries to it. I then logged into your site and created a test post named HG Test and deleted it. It took about 2-3 seconds for this action to complete which is slightly slower than normal but not by much. I also see that you have several plugins that are most likely being called when these actions are taking place which is likely the culprit here.
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Google XML Sitemaps
WP Sitemap Page
WordPress SEO
WP-PostViews
Contextual Related Posts
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Plugins are normally the cause of any slow speed issues with WordPress. I would suggest disabling all of your plugins for testing purposes and then re-enable each of them one at a time testing in between each one. This way you can find the plugin causing this issue.

If you have any further questions or need additional assistance, please let us know.
Thanks and have a great day!

John P.
Linux Systems Administrator
HostGator, LLC
https://support.hostgator.com/

Though the email chat support took some time to initiate, it also gave a similar solution. Another noticeable thing is that, my WordPress websites automatically update to the newer versions. Though updates like 3.8.3, 3.9.0 didn’t cause any problem, 3.9.1 noticeably slowed my WordPress Admin operations.

Wordpress Panel Slow

How To Activate Deactivate WordPress Plugins At once

The Solution

So if you are facing a similar problem like mine, first de-activate all your plugins. Then try to activate each plugin one by one. Or else, you can re-activate all of them again at once, using the check-box option present in WordPress Admin panel. This should normally bring back the speed of your WordPress saves, edits, deletes etc, it’s also important that you have as few plugins as possible.

This also impacts the site loading speed and Admin panel operations.