High CPU usage when swtiching theme

Is this on multisite or anything specific? How many product images do you have?

It can be disabled via a filter, and 3.3.2 will have a link to cancel the resize process, but I wonder why it would be a problem for your host vs any other regen plugin such as https://en-gb.www.ads-software.com/plugins/regenerate-thumbnails/ – they all work in a similar fashion.

Stuff like this usually happens on cheap, crappy hosts. I can’t speak as to whether this is the case in this situation or not (I don’t know who your host is), but it’s suspicious that a host is issuing a warning for using the CPU for a while in order to generate some new thumbnail images. That’s not that unusual of a thing to be doing.

Personally I’d install Jetpack and enable the Image CDN functionality. This will offload image serving and more importantly thumbnail generation to the WordPress.com servers.

• This reply was modified 7 years ago by viper007bond.

My website is not a multisite, nothing especially unique but just a regular website I would like to use for event registration.

I’m using the Siteground hosting plans, and have tried on both the StartUp and GrowBig plans. Have installed the Jackpack and activated their image feature as well. When I switch theme with the Woocemmerce plugin, it keeps generate the POST /wp-admin/admin-ajax.php?action=wp_1_wc_regenerate_images and boost the CPU to a very high usage. The Siteground warned me if I generate than high volume again, I will be blocked.

I never use https://en-gb.www.ads-software.com/plugins/regenerate-thumbnails/ and don’t have similar plugin on my site.

Resizing images is CPU intensive. This happens whenever you upload an image to WP (usually) so I’m unsure why the host would mind unless it’s a shared host (which may not be ideal for eCommerce anyway).

In 3.3.2 we’ve changed our code to disable background processing when Jetpack Photon is present, since it’s not needed. This should be out next week, however, we’ve pushed out a pre-release version to .org (3.3.2-rc.1) so if you’d like to help test that you can do so using a plugin like “WP Rollback” to switch to that version before it’s released officially.

Yes, I’m using a shared hosting, but there is no traffic on my account because it’s a testing site for my development. However, I don’t want to risk my productive site on this plugin.

The high CPU usage is caused when I tried to switch theme, so I guess the system was trying to regenerate the thumbnails all at once, and this is what make the hosting initial an alert. Resizing one individual image might be not as intensive as when all images are regenerating. In addition, I don’t think it is a favorable behavior as well. There is no reason to resize the thumbnail or existing image because a user switch theme.

@kaoruc Have you retested this with the newest version of WooCommerce?

We haven’t heard back from you in a while, so I’m going to mark this as resolved – if you have any further questions, you can start a new thread.