Slow-opening pyinstaller-generated EXE

[enricodragoni]

Hi All,

I am using pyinstaller to generate an exe file from my python script, with the following set-up:

• Python 3.11.9
• Pyinstaller 6.12.0
• Working with Virtual Environment
• In the venv I have plently of python packages that are needed (plotly, pandas, kaleido, etc.) with some of them being "heavy"
• I run pyinstaller with the following command: .\.env\Scripts\pyinstaller.exe --clean --noconfirm .\scripts\Analysis\MyScript.spec
• In my .spec file I do not have any particular setting: another exe is bundled together through Analysis.binaries, EXE.upx=True, EXE.console=true
• The generated exe is about 125 MB
• Opening the exe for the first time takes about 25 seconds (I guess he needs to unpacks stuff at the first opening) and from the second time onwards it takes 10 seconds
• With "Opening" I mean that there is tkinter-implemented GUI launched by the script's main function that would ideally appear after few seconds after clicking on the exe.

I have tried to do "lazy imports", i.e. minimizing the imports at the beginning of my script but this didn't reduce significantly the opening time.
I assume no issue with my antivirus.
Any ideas on how to get this EXE opening quicker? Thanks in advance.

[bwoodsend]

Are you using onefile mode?

It would help if you can identify if the startup delay comes from before or after all the data science monstrosities libraries (just adding print statements before and after the imports would do).

And just to confirm, you're not running this off a synced/network drive or some other artificial file system?

[enricodragoni]

I am using the onefile mode. I understood that when calling pyinstaller with a .spec file, the onefile mode is the default mode.
I am running the exe from my C:.
I have also tried to add some print statements before and after the imports: the both come in "very late", i.e. just 2 second before the final opening. This confirms the trial I made with lazy imports, which in fact reduced the opening time of 1-2 seconds

[bwoodsend]

I understood that when calling pyinstaller with a .spec file, the onefile mode is the default mode.

A spec file is in whatever mode you specified when you generated it. pyinstaller xyz.py creates a onedir spec and pyinstaller --onefile xyz.py creates a onefile spec.

Give onedir mode a go. Onefile mode doesn't scale well on Windows.

[enricodragoni]

Thanks!
Indeed I was confused about the proper usage of the .spec file, it is clear now.
My "new" .spec file not using the --onefile option anymore generates the exe inside a directory which opens up much quicker. The downside is obviously that the entire directory has to be carried around.