Administrator Cache folder in Joomla 5 Topic is solved

[sgiobbio]

After upgrading to Joomla 5, which succeeded without problems, I encounter an issue that would seem to be new:
the Administrator Cache fills up with files (enough to create problems with the global Inodes allowed in my Shared Hosting), despite the fact that in Global Configuration the cache is disabled, the System - Page plugin Cache is disabled, and the Component Cache Administrator appears to be disabled.
In particular, the administrator>cache>preview and the administrator>cache>thumb folders become huge.
Has anyone encountered the same problem? Any solutions?
I would like to avoid installing an add-on that empties cache automatically at regular intervals, rather I prefer a cron job from cPanel.
I would like to know from someone who knows the joomla structure thoroughly what the cache folder in administrator is for.
I found article images in there, and I don't understand what they have to do with administrator.

[Webdongle]

System>>> maintenance... Clear cache

[sgiobbio]

Of course I did clear cache, that's the first thing I did.
But clearing cache doesn't solve the issue of a cache that fills up even if it's disabled!

[toivo]

Has anyone encountered the same problem? Any solutions?

A few days ago someone else asked about the folder administrator/cache/schemaorg, where caching stores Rich Snippets, the new feature in Joomla 5.

I would like to know from someone who knows the joomla structure thoroughly what the cache folder in administrator is for.

It is used for caching by all the core components, modules and Media. This Joomla document explains the different options to manage caching: Cache.

There are options to automate the purging of the cache files. Develop a script and run it as a cron job from the operating system or as a scheduled task from Joomla. The paid extension Admin Tools Pro adds a task 'Admin Tools – Cache clean-up' into the Scheduled Tasks of Joomla. There may be other extensions in JED that do the same, for example Cache Cleaner.

[brian]

There is nothing in the core of joomla that creates the folders you described (administrator/cache/preview and administrator/cache/thumbs) so they must be being created by an extension you have installed

[sgiobbio]

as also suggested by toivo, I ran a script as a cron job to purge the cache. So in my own way I solved the issue.
But I wonder if there is not a way to set NO CACHE in administrator for the folders administrator/cache/preview and administrator/cache/thumbs
In Brian's opinion "there is nothing in the core of joomla that creates these folders" but I don't use third party extensions except for the bare minimum:
GDPR, by J!Extensions Store
OsMap
Plugin Embed Google Map
PDF Embed
Sigplus
Ochjssocial light
And nothing else.
It doesn't seem to me that any of these extensions could be responsible for creating those folders

[brian]

not my opinion - its a fact!!

[Webdongle]

Sigplus creates thumbs, so it could easily produce cache in administrator?

[sgiobbio]

I did not mean to question Brian's statements, and I apologize if I misspoke.
I thank Webdongle for the suggestion about Sigplus and will do some checking.
I do not understand why Sigplus should create a cache in the administrator, but if I find out that this is the reason, I will ask the developer and report back here.

[Webdongle]

Sigplus creates thumbs while you are making choices in Admin. Where else would it store cache?

Correction it is module and plugin not a Component

Ok
installed sigplus on a test site
Enabled the plugin
Set the module to display on all pages with images from test data
/administrator/cache/thumb appeared with images that were displayed in the module

Changed target folder
/administrator/cache/thumb had the previous images and the new images

Clearing cache in Joomla clears /administrator/cache/thumb folder and it's content!!!

[sgiobbio]

Excellent test, Webdongle. Thank you.
Having established that sigplus is responsible, I will clear the cache with a cronjob.
But I still don't understand what is the point of filling a folder in Administration with thumbs, I could understand it in the site cache folder, but not in Administration. For what purpose?

[Webdongle]

That is a question best asked of the devs who created sigplus