[Tutor] in a pickle about pickle

[nathan tech]

Hi there,


I asked this question on stackoverflow, but realised I'd probably get 
better answers here and should have have asked here in the first place 
as the questions are a little bit newbieish.


I've done a lot of work with pickle, though only recently come across 
cPickle which is faster (aparrently).


I was wondering though if someone would be able to answer these 
questions for me though:

1. does pickle.dump(obj, file, protocol) thread itself in any way?

2. When I do something like: pickle.dump(obj, file, 2) the file that is 
put out is still, mostly, human readable. Is this normal? It talks about 
bytes in the docs which I took to mean it would not be human readable.


Related to this I also wanted to ask is there a way to see what function 
is hanging a python process?

Allow me to explain this further as the obvious answers may not apply:

I have a program which has a graphical user interface through wx python. 
As part of this program it saves data to files using pickle, because 
they're dictionaries. I could use xml2dict and dict2xml, but cPickle is 
faster (I think).

It executes the saving when you click a button. This occurs, the python 
program freezes for a second, then goes bacck to the GUI. that's fine, 
expected behaviour.

If I then click exit it returns to the console (expected), and then 
sometimes will just sit there for about 10 to 15 minutes before finally 
finishing.

I went into task manager and killed the task once, and found that the 
data files were only half written, which is what leads me to believe it 
is pickle that is either locking up or taking forever.

Annoyingly, since I played around with msgpack, json and then back to 
cPickle it's not been doing it since, but I have observed this behaviour 
with another one of my programs too.


Is this an issue that comes up often with pickle?


I work mostly with python dictionaries when dumping to files, which is 
why I figured pickle would be the best option.


Thanks a lot for any help

Nathan