Upgrading your OS could result in the indexed search database to become
rebuild, and this can take a very(!) long time and meanwhile painfully
rendering your system almost unresponsive until the database is fully
recreated. I am speaking about days, on old hardware. I have had this,
and diagnosis patterns showed pretty much the same as you described it.
I assume that you have maybe GNOME or KDE Plasma in use. At least these
desktop environments (I do not know about the many others) come with
this indexing feature running in the background. It is indexing all
files in the home directory to a database, not only registering file
names but possibly also creating a full text index of all file content.
This database later on helps the user a lot when searching for something
in the filesystem: the system answers significantly faster than only
upon the user's search starting to crawl through all the file system.
Also, the answer is usually also more broadened if full text indexing
was activated instead of file name indexing only. In principal, a nice
feature! But...
While in the background adding information to the index whenever a new
file is added to the home directory is almost unnoticed by the user, the
first time creation (or recreation) of the index is a painful system
load when running over many files at once. Example: the recreation of
the index database for some 10 GB of mixed data (PDF, DOC, JPG, etc.) in
a home directory could easily take some 10 to 20 hours on Core2Duo
laptop from 2009 with 3GB RAM and USB2 connected disk holding the to be
indexed data. As long as this indexing process hasn't finished, the
system is rendered almost unusable, it almost does not respond anymore.
Watching out for the CPU load of this process might not make it become
obvious right away, because it usually has a "nice" value of 19, meaning
only to use the CPU if it is idle regarding other processes. Therefore
you see usually the other process requesting CPU time, while the index
engine produced load stays shadowed. But, the usage of I/O, access to
the disk and the database, can still be very heavy and slow your system
down until it is almost no more responsive!
I only remember, that on GNOME this indexing engine in the past was
called "zeitgeist" and cannot guide you more with this one.
On KDE it is called "baloo" and here I would recommend you to try the
following command "balooctl disable". If you are lucky, then your
problem is solved. Also, double check for its setting in the GUI by
going to " SYSTEM SETTINGS - Workspace - Search - File Search" and check
that it is also deactivated there. This setting in the GUI in the end
also controls baloo. However the CLI and GUI are not well synchronized,
in my experience, and therefore better check both places. If this was
the problem, then maybe investigate for a long term solution by the
command "balooctl config show", or directly have a look at files called
"baloo*" in the hidden directory "$USER/.config" .
I am still curious to read about the outcome of your investigations.
Wishing you all the best!
Marco
