Hi @petr.zelenka , welcome to the forum!
As per the following forum article, can you confirm that you are running the latest Couchbase Python SDK:
https://www.couchbase.com/forums/t/memory-leak-with-python-couchbase-2-5-0/21055/10
With python sdk version [3.2.4], this problem is fixed.
Just upgrade sdk to version 3.2.4 with
python3 -m pip install --upgrade couchbase
The relevant Jira issue ticket is here:
https://issues.couchbase.com/browse/PYCBC-995
And the fix commit here:
https://github.com/couchbase/couchbase-python-client/commit/e5e2f732f887e9342bc91799d6c7b034698ffe53
I hope that helps!