Help setting up PDF search and OCR

Dear All,

First of all, thank you in advance for Your time on this.

I am trying to setup PDF full image/text search (some PDFs are just images and not text) in my NextCloud 25.0.6 instance. It runs on Rokcy Linux 8 (fully updated) as a web page, served by the host’s apache server (not running as container image or virtual image).

Googling around and searching in this forum, I started by installing Tesseract and adding the English language for start.

Under Admin → Administration → Full Text Search, I could see nothing but “General Settings” with the “Search Platform” empty. Also show in the bellow screenshot.

Then again looking for information in the Wiki I concluded (maybe wrongly?) that I have to install ElasticSearch.

So I did.

At that point, the Search Platform option could be populated (Elasticsearch was an option) and only then the Tessearct OCR options became available.

All the above, as the admin user.

I do have a small doubt about the elasticsearch part specifically the url setting as the installation is using certs for authentication:

Now I login as a non-admin user and create a flow.

And I also add the following with crontab -u apache -e:

*/5 * * * * php -f /mnt/services//www/html/nextcloud/cron.php

At this point I expect as a non admin user:

  1. Adding the OCR tag to a pdf file, this to be OCRed.
  2. Searching words contained in the pdf (English language pdf) to return results pointing to that document
  3. The cron job to do something (but what???)

What I actually have is:

  1. Adding the OCR tag to a pdf, does not seam to OCR it.
  2. The disks are 100% active. Tools for tracing activity (iotop, top, ps etc) show that there php -f /mnt/services//www/html/nextcloud/cron.php is running all the time (doing what?) and mariadb is constantly updating tuples.

So my questions:

  1. Do I correctly think that Tessaract ocr will actually fully ocr any English pdf document with the OCR tag assigned to it?
  2. Are the above steps take correct towards that?
  3. Am I missing something?
  4. Do I have a correct test case (assign the OCR tag to a pdf & wait for it to be indexed)?
  5. Where does elasticsearch fit in the setup?
  6. Why is the system (cron.php / mysql) so busy? Doing what? How to find out?

Much appreciated.