I noticed this because when I ran history -g to print my full ipython history from the beginning of time, it completed in about half a second when I was in ipython version 9.0.2 or below. Starting with v9.1.0 and above, history -g takes an astronomical 30 seconds to go through the process of printing these many thousands of line to the terminal.

The problem isn't specific to the history command, because just printing a ton of numbers to the terminal shows the same pattern – For me, the following takes about 1 second on ipython v9.0.2 but over a minute on ipython v9.1.0:

for i in range(1_000_000):
    print(i)

I'm on an M1 Macbook, and have gotten this same behavior in both python 3.11 and 3.12. (For lower versions of python, there doesn't seem to be a wheel available to install ipython version 9.x.x, so those versions of python stay with ipython version 8.x.x)

Can anyone else reproduce this?