ikhal is really slow

Generally speaking, the concept behind khal is awesome. I got it to work fine with my google calendar. That calendar has only few items, and ikhal's navigation is seamless.

However, I am also trying to use this for my office calendar at work, where I have tons of meeting events (total ~300 ics files, totaling ~5MB in vdir). In this setup, the same ikhal installation is very slow (~5 seconds) both to startup and to navigate in the calendar view (hangs a lot).

I am using a MacOSX (Darwin Kernel Version 16.7.0), Python 3.7.0, khal 0.9.9 based on pip3 install (global installation without virtualenv).

I tried the simple non-pkg_resources variant

#!/usr/bin/env python3

from khal.cli import main_khal

main_khal()

but that did not change anything noticeable.

I profiled khal with the default invocation and got khal.profile.tar.gz based on python3 cProfile which I cannot fully understand since I don't know all the function names. But it seems like a lot of time is being spent in parser.py. Pardon me if I am mistaken.

Could you please help me out.

The report points to parser.py and includes khal.profile.tar.gz; begin by examining the cProfile data and reproducing the delay with the stated ~300 ICS files. Done means identifying and addressing the startup and calendar-navigation slowdown, then measuring those paths again.