I had a problem recently with Vim.

Saving a 54K python file took a very long time (sometimes close to a minute). I thought this was due to Vim and tried to save the same file to a .sql file.

It saves in a zip.

So, the problem was with .py alone.

I checked vim’s au commands, and found nothing suspicious there too.

Next, I checked the plugins and narrowed down to the plugins I added.

Turned out that the python_fold.vim plugin was the culprit.

It was recomputing the folds in the whole file everytime I  saved.

I abandoned the plugin. There’s another similar plugin python_ifold.vim out there but I don’t need an auto-fold plugin for python at the moment.

For the moment, I am happy that .py files save zippily.